Laboratory-scale carbon anodes were produced by a new method of high temperature mould pressing, and their physico-chemical properties were studied. The influence of mould pressing conditions and coal pitch addition o...Laboratory-scale carbon anodes were produced by a new method of high temperature mould pressing, and their physico-chemical properties were studied. The influence of mould pressing conditions and coal pitch addition on the bulk density, crushing strength, and oxidation resistance was analyzed. The mierostructure of carbon anodes was investigated by scanning electron microscopy （SEM）, and the mechanism of producing carbon anodes by high-temperature mould pressing was analyzed. The results show that when the anodes are produced by high-temperature mould pressing, coal pitch can expand into the coke particles and fill the pores inside the particles, which is beneficial for improving the quality of prebaked anodes. The bulk density of carbon anodes is 1.64-1.66 g/cm3, which is 0.08-0.12 g/cm3 higher than that of industrial anodes, and the oxidation resistance of carbon anodes is also significantly improved.展开更多
Silicon(Si)has been studied as a promising alloying type anode for lithium-ion batteries due to its high specific capacity,low operating potential and abundant resources.Nevertheless,huge volume expansion during alloy...Silicon(Si)has been studied as a promising alloying type anode for lithium-ion batteries due to its high specific capacity,low operating potential and abundant resources.Nevertheless,huge volume expansion during alloying/dealloying processes and low electronic conductivity of Si anodes restrict their electrochemical performance.Thus,carbon(C)materials with special physical and chemical properties are applied in Si anodes to effectively solve these problems.This review focuses on current status in the exploration of Si/C anodes,including the lithiation mechanism and solid electrolyte interface formation,various carbon sources in Si/C anodes,such as traditional carbon sources(graphite,pitch,biomass),and novel carbon sources(MXene,graphene,MOFs-derived carbon,graphdiyne,etc.),as well as interfacial bonding modes of Si and C in the Si/C anodes.Finally,we summarize and prospect the selection of carbonaceous materials,structural design and interface control of Si/C anodes,and application of Si/C anodes in all-solid-state lithium-ion batteries and sodium-ion batteries et al.This review will help researchers in the design of novel Si/C anodes for rechargeable batteries.展开更多
The resourceful and inexpensive red phosphorus has emerged as a promising anode material of potassium-ion batteries(PIBs) for its large theoretical capacities and low redox potentials in the multielectron alloying/dea...The resourceful and inexpensive red phosphorus has emerged as a promising anode material of potassium-ion batteries(PIBs) for its large theoretical capacities and low redox potentials in the multielectron alloying/dealloying reactions,yet chronically suffering from the huge volume expansion/shrinkage with a sluggish reaction kinetics and an unsatisfactory interfacial stability against volatile electrolytes.Herein,we systematically developed a series of localized high-concentration electrolytes(LHCE) through diluting high-concentration ether electrolytes with a non-solvating fluorinated ether to regulate the formation/evolution of solid electrolyte interphases(SEI) on phosphorus/carbon(P/C) anodes for PIBs.Benefitting from the improved mechanical strength and structural stability of a robust/uniform SEI thin layer derived from a composition-optimized LHCE featured with a unique solvation structure and a superior K+migration capability,the P/C anode with noticeable pseudocapacitive behaviors could achieve a large reversible capacity of 760 mA h g^(-1)at 100 mA g^(-1),a remarkable capacity retention rate of 92.6% over 200 cycles at 800 mA g^(-1),and an exceptional rate capability of 334 mA h g^(-1)at8000 mA g^(-1).Critically,a suppressed reduction of ether solvents with a preferential decomposition of potassium salts in anion-derived interfacial reactions on P/C anode for LHCE could enable a rational construction of an outer organic-rich and inner inorganic-dominant SEI thin film with remarkable mechanical strength/flexibility to buffer huge volume variations and abundant K+diffusion channels to accelerate reaction kinetics.Additionally,the highly reversible/durable full PIBs coupling P/C anodes with annealed organic cathodes further verified an excellent practical applicability of LHCE.This encouraging work on electrolytes regulating SEI formation/evolution would advance the development of P/C anodes for high-performance PIBs.展开更多
Sodium-ion batteries(SIBs)have attracted significant attentions as promising alternatives to lithium-ion batteries for large-scale energy storage applications.Here carbon materials are considered as the most competiti...Sodium-ion batteries(SIBs)have attracted significant attentions as promising alternatives to lithium-ion batteries for large-scale energy storage applications.Here carbon materials are considered as the most competitive anodes for SIBs based on their low-cost,abundant availability and excellent structural stability.Pitch,with high carbon content and low cost,is an ideal raw precursor to prepare carbon materials for large-scale applications.Nevertheless,the microstructures of pitch-based carbon are highly ordered with smaller interlayer distances,which are unfavorable for Na ion storage.Many efforts have been made to improve the sodium storage performance of pitch-based carbon materials.This review summarizes the recent progress about the application of pitch-based carbons for SIBs anodes in the context of carbon’s morphology and structure regulation strategies,including morphology adjustment,heteroatoms doping,fabricating heterostructures,and the increase of the degree of disorder.Besides,the advantages,present challenges,and possible solutions to current issues in pitch-based carbon anode are discussed,with the highlight of future research directions.This review will provide a deep insight into the development of low-cost and high-performance pitch-based carbon anode for SIBs.展开更多
Biomass-derived hard carbons,usually prepared by pyrolysis,are widely considered the most promising anode materials for sodium-ion bat-teries(SIBs)due to their high capacity,low poten-tial,sustainability,cost-effectiv...Biomass-derived hard carbons,usually prepared by pyrolysis,are widely considered the most promising anode materials for sodium-ion bat-teries(SIBs)due to their high capacity,low poten-tial,sustainability,cost-effectiveness,and environ-mental friendliness.The pyrolysis method affects the microstructure of the material,and ultimately its so-dium storage performance.Our previous work has shown that pyrolysis in a sealed graphite vessel im-proved the sodium storage performance of the car-bon,however the changes in its microstructure and the way this influences the sodium storage are still unclear.A series of hard carbon materials derived from corncobs(CCG-T,where T is the pyrolysis temperature)were pyrolyzed in a sealed graphite vessel at different temperatures.As the pyrolysis temperature increased from 1000 to 1400℃ small carbon domains gradually transformed into long and curved domains.At the same time,a greater number of large open pores with uniform apertures,as well as more closed pores,were formed.With the further increase of pyrolysis temperature to 1600℃,the long and curved domains became longer and straighter,and some closed pores gradually became open.CCG-1400,with abundant closed pores,had a superior SIB performance,with an initial reversible ca-pacity of 320.73 mAh g^(-1) at a current density of 30 mA g^(-1),an initial Coulomb efficiency(ICE)of 84.34%,and a capacity re-tention of 96.70%after 100 cycles.This study provides a method for the precise regulation of the microcrystalline and pore structures of hard carbon materials.展开更多
Constructing silicon(Si)-based composite electrodes that possess high energy density,long cycle life,and fast charging capability simultaneously is critical for the development of high performance lithium-ion batterie...Constructing silicon(Si)-based composite electrodes that possess high energy density,long cycle life,and fast charging capability simultaneously is critical for the development of high performance lithium-ion batteries for mitigating range anxiety and slow charging issues in new energy vehicles.Herein,a thick silicon/carbon composite electrode with vertically aligned channels in the thickness direction(VC-SC)is constructed by employing a bubble formation method.Both experimental characterizations and theoretical simulations confirm that the obtained vertical channel structure can effectively address the problem of sluggish ion transport caused by high tortuosity in conventional thick electrodes,conspicuously enhance reaction kinetics,reduce polarization and side reactions,mitigate stress,increase the utilization of active materials,and promote cycling stability of the thick electrode.Consequently,when paired with LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622),the VC-SC||NCM622 pouch type full cell(~6.0 mAh cm^(-2))exhibits significantly improved rate performance and capacity retention compared with the SC||NCM622 full cell with the conventional silicon/carbon composite electrode without channels(SC)as the anode.The assembled VC-SC||NCM622 pouch full cell with a high energy density of 490.3 Wh kg^(-1)also reveals a remarkable fast charging capability at a high current density of 2.0 mA cm^(-2),with a capacity retention of 72.0%after 500 cycles.展开更多
Carbon-based materials are recognized as anodes fulling of promise for potassium ion batteries(PIBs)due to advantages of affordable cost and high conductivity.However,they still face challenges including structural un...Carbon-based materials are recognized as anodes fulling of promise for potassium ion batteries(PIBs)due to advantages of affordable cost and high conductivity.However,they still face challenges including structural unstability and slow kinetics.It is difficult to achieve efficient potassium storage with unmodified carbonaceous anode.Herein,atomic bismuth(Bi)sites with different atom coordinations anchored on carbon nanosheets(CNSs)have been synthesized through a template method.The properties of prepared multi-doping carbon anodes Bi-N_(3)S_(1)/CNSs,Bi-N_(3)P_(1)/CNSs and Bi-N_(4)/CNSs were probed in PIBs.The configuration Bi-N_(3)S_(1) with stronger charge asymmetry exhibits superior potassium storage performance compared to Bi-N_(3)P_(1) and Bi-N_(4) configurations.The Bi-N_(3)S_(1)/CNSs display a rate capacity of 129.2 mAh g^(-1)even at 10 A g^(-1)and an impressive cyclability characterized by over 5000 cycles at 5 A g^(-1),on account of its optimal coordination environment with more active Bi centers and K^(+)adsorption sites.Notably,assembled potassium-ion full cell Mg-KVO//Bi-N_(3)S_(1)/CNSs also shows an outstanding cycling stability,enduring 3000 cycles at 2 A g^(-1).Therefore,it can be demonstrated that regulating the electronic structure of metallic centre M-N_(4) via changing the type of ligating atom is a feasible strategy for modifying carbon anodes,on the base of co-doping metal and non-metal.展开更多
Red phosphorus has been well-recognized as promising anode materials for lithium-ion batteries(LIBs)and potassium-ion batteries(PIBs)due to its extremely high theoretical capacity and low cost.However,the huge volume ...Red phosphorus has been well-recognized as promising anode materials for lithium-ion batteries(LIBs)and potassium-ion batteries(PIBs)due to its extremely high theoretical capacity and low cost.However,the huge volume change and poor electric conductivity severely limit its further practical application.Herein,the nanoscale ultrafine red phosphorus has been successfully confined in a three-dimensional pitch-based porous carbon skeleton composed of well-interconnected carbon nanosheets through the vaporization-condensation method.Except for the traditional requirement of high electric conductivity and stable mechanical stability,the micropores and small mesopores in the porous carbon matrix centered at 1 to 3 nm and the abundant amount of oxygen-containing functional groups are also beneficial for the high loading and dispersion of red phosphorus.As anode for LIBs,the composite exhibits high reversible discharge capacities of 968 mAh g^(-1),excellent rate capabilities of 593 mAh g^(-1)at 2 A g^(-1),and long cycle performance of 557 mAh g^(-1)at 2 A g^(-1).More impressively,as the anode for PIBs,the composite presents a high reversible capacity of 661 mAh g^(-1)and a stable capacity of 312 mAh g^(-1)at 0.5 A g^(-1)for 500 cycles with a capacity retention up to 84.3%.This work not only sheds light on the structure design of carbon hosts with specific pore structure but also open an avenue for high value-added utilization of coal tar pitch.展开更多
The corrosion inhibition efficacy of titanate(CaTiO_(3))for carbon anodes in molten salts was investigated through various analytical techniques,including linear sweep voltammetry,X-ray diffraction,scanning electron m...The corrosion inhibition efficacy of titanate(CaTiO_(3))for carbon anodes in molten salts was investigated through various analytical techniques,including linear sweep voltammetry,X-ray diffraction,scanning electron microscopy,and energy dispersion spectroscopy.The results demonstrate that the addition of CaTiO_(3)corrosion inhibitor efficiently passivates the carbon anode and leads to the formation of a dense CaTiO_(3)layer during the electrolysis process in molten CaCl_(2)-CaO.Subsequently,the passivated carbon anode effectively undergoes the oxygen evolution reaction,with an optimal current density for passivation identified at 400 m A/cm^(2).Comprehensive investigations,including CaTiO_(3)solubility tests in molten CaCl_(2)-CaO and numerical modeling of the stability of complex ionic structures,provide compelling evidence supporting“complexation-precipitation”passivation mechanism.This mechanism involves the initial formation of a complex containing TiO_(2)·nCaO by CaTiO_(3)and CaO,which subsequently decomposes to yield CaTiO_(3),firmly coating the surface of the carbon anode.In practical applications,the integration of CaTiO_(3)corrosion inhibitor with the carbon anode leads to the successful preparation of the FeCoNiCrMn high-entropy alloy without carbon contamination in the molten CaCl_(2)-CaO.展开更多
Recent technological advancements,such as portable electronics and electric vehicles,have created a pressing need for more efficient energy storage solutions.Lithium-ion batteries(LIBs)have been the preferred choice f...Recent technological advancements,such as portable electronics and electric vehicles,have created a pressing need for more efficient energy storage solutions.Lithium-ion batteries(LIBs)have been the preferred choice for these applications,with graphite being the standard anode material due to its stability.However,graphite falls short of meeting the growing demand for higher energy density,possessing a theoretical capacity that lags behind.To address this,researchers are actively seeking alternative materials to replace graphite in commercial batteries.One promising avenue involves lithiumalloying materials like silicon and phosphorus,which offer high theoretical capacities.Carbon-silicon composites have emerged as a viable option,showing improved capacity and performance over traditional graphite or pure silicon anodes.Yet,the existing methods for synthesizing these composites remain complex,energy-intensive,and costly,preventing widespread adoption.A groundbreaking approach is presented here:the use of a laser writing strategy to rapidly transform common organic carbon precursors and silicon blends into efficient“graphenic silicon”composite thin films.These films exhibit exceptional structural and energy storage properties.The resulting three-dimensional porous composite anodes showcase impressive attributes,including ultrahigh silicon content,remarkable cyclic stability(over 4500 cycles with∼40%retention),rapid charging rates(up to 10 A g^(-1)),substantial areal capacity(>5.1 mAh cm^(-2)),and excellent gravimetric capacity(>2400 mAh g^(-1) at 0.2 A g^(-1)).This strategy marks a significant step toward the scalable production of high-performance LIB materials.Leveraging widely available,cost-effective precursors,the laser-printed“graphenic silicon”composites demonstrate unparalleled performance,potentially streamlining anode production while maintaining exceptional capabilities.This innovation not only paves the way for advanced LIBs but also sets a precedent for transforming various materials into high-performing electrodes,promising reduced complexity and cost in battery production.展开更多
To achieve high energy density in lithium batteries,the construction of lithium-ion/metal hybrid anodes is a promising strategy.In particular,because of the anisotropy of graphite,hybrid anode formed by graphite/Li me...To achieve high energy density in lithium batteries,the construction of lithium-ion/metal hybrid anodes is a promising strategy.In particular,because of the anisotropy of graphite,hybrid anode formed by graphite/Li metal has low transport kinetics and is easy to causes the growth of lithium dendrites and accumulation of dead Li,which seriously affects the cycle life of batteries and even causes safety problems.Here,by comparing graphite with two types of hard carbon,it was found that hybrid anode formed by hard carbon and lithium metal,possessing more disordered mesoporous structure and lithophilic groups,presents better performance.Results indicate that the mesoporous structure provides abundant active site and storage space for dead lithium.With the synergistic effect of this structure and lithophilic functional groups(–COOH),the reversibility of hard carbon/lithium metal hybrid anode is maintained,promoting uniform deposition of lithium metal and alleviating formation of lithium dendrites.The hybrid anode maintains a 99.5%Coulombic efficiency(CE)after 260 cycles at a specific capacity of 500 m Ah/g.This work provides new insights into the hybrid anodes formed by carbon-based materials and lithium metal with high specific energy and fast charging ability.展开更多
Developing effective strategies to improve the initial Coulombic efficiency(ICE)and cycling stability of hard carbon(HC)anodes for sodium-ion batteries is the key to promoting the commercial application of HC.In this ...Developing effective strategies to improve the initial Coulombic efficiency(ICE)and cycling stability of hard carbon(HC)anodes for sodium-ion batteries is the key to promoting the commercial application of HC.In this paper,homotype heterojunctions are designed on HC to induce the generation of stable solid electrolyte interfaces,which can effectively increase the ICE of HC from 64.7%to 81.1%.The results show that using a simple surface engineering strategy to construct a homotypic amorphous Al_(2)O_(3) layer on the HC could shield the active sites,and further inhibit electrolyte decomposition and side effects occurrence.Particularly,due to the suppression of continuous decomposition of NaPF 6 in ester-based electrolytes,the accumulation of NaF could be reduced,leading to the formation of thinner and denser solid electrolyte interface films and a decrease in the interface resistance.The HC anode can not only improve the ICE but elevate its sodium storage performance based on this homotype heterojunction composed of HC and Al_(2)O_(3).The optimized HC anode exhibits an outstanding reversible capacity of 321.5mAhg^(−1) at 50mAg^(−1).The cycling stability is also improved effectively,and the capacity retention rate is 86.9%after 2000 cycles at 1Ag^(−1) while that of the untreated HC is only 52.6%.More importantly,the improved sodium storage behaviors are explained by electrochemical kinetic analysis.展开更多
Based on the hexagonal crystallite model of graphite,the electrochemical characteristics of carbon atoms on the edge and basal plane were proposed by analyzing graphite crystal structure and bonds of carbon atoms in d...Based on the hexagonal crystallite model of graphite,the electrochemical characteristics of carbon atoms on the edge and basal plane were proposed by analyzing graphite crystal structure and bonds of carbon atoms in different sites.A spherical close-packed model for graphite particle was developed.The fractions of surface carbon atoms（SCA） and edge carbon atoms（ECA） were derived in the expression of crystallographic parameters and particle size,and the effects of ECA on the initial irreversible capacity and the mechanisms of action were analyzed and verified.The results show that the atoms on the edge are more active for electrochemical reactions,such as electrolyte decomposition and tendency to form stable bond with other atoms and groups.For the practical graphite particle,corresponding modifying factors were introduced to revise the difference in calculating results.The revised expression is suitable for the calculation of the fractions of SCA and ECA for carbon materials such as graphite,disordered carbon and modified graphite.展开更多
Pore structure of hard carbon has a fundamental influence on the electrochemical properties in sodium-ion batteries(SIBs).Ultra-micropores(<0.5 nm)of hard carbon can function as ionic sieves to reduce the diffusion...Pore structure of hard carbon has a fundamental influence on the electrochemical properties in sodium-ion batteries(SIBs).Ultra-micropores(<0.5 nm)of hard carbon can function as ionic sieves to reduce the diffusion of slovated Na+but allow the entrance of naked Na^(+) into the pores,which can reduce the interficial contact between the electrolyte and the inner pores without sacrificing the fast diffusion kinetics.Herein,a molten diffusion-carbonization method is proposed to transform the micropores(>1 nm)inside carbon into ultra-micropores(<0.5 nm).Consequently,the designed carbon anode displays an enhanced capacity of 346 mAh g^(−1) at 30 mA g^(−1) with a high ICE value of~80.6%and most of the capacity(~90%)is below 1 V.Moreover,the high-loading electrode(~19 mg cm^(−2))exhibits a good temperature endurance with a high areal capacity of 6.14 mAh cm^(−2) at 25℃ and 5.32 mAh cm^(−2) at −20℃.Based on the in situ X-ray diffraction and ex situ solid-state nuclear magnetic resonance results,the designed ultra-micropores provide the extra Na+storage sites,which mainly contributes to the enhanced capacity.This proposed strategy shows a good potential for the development of high-performance SIBs.展开更多
Studies have found that oxygen-rich-containing functional groups in carbon-based materials can be used as active sites for the storage performance of K^(+),but the basic storage mechanism is still unclear.Herein,we co...Studies have found that oxygen-rich-containing functional groups in carbon-based materials can be used as active sites for the storage performance of K^(+),but the basic storage mechanism is still unclear.Herein,we construct and optimize 3D honeycomb-like carbon grafted with plentiful COOH/C=O functional groups(OFGC)as anodes for potassium ion batteries.The OFGC electrode with steady structure and rich functional groups can effectively contribute to the capacity enhancement and the formation of stable solid electrolyte interphase(SEI)film,achieving a high reversible capacity of 230 mAh g^(-1) at 3000 mA g^(-1) after 10,000 cycles(almost no capacity decay)and an ultra-long cycle time over 18 months at 100 mA g^(-1).The study results revealed the reversible storage mechanism between K^(+)and COOH/C=O functional groups by forming C-O-K compounds.Meanwhile,the in situ electrochemical impedance spectroscopy proved the highly reversible and rapid de/intercalation kinetics of K+in the OFGC electrode,and the growth process of SEI films.In particular,the full cells assembled by Prussian blue cathode exhibit a high energy density of 113 Wh kg^(-1) after 800 cycles(calculated by the total mass of anode and cathode),and get the light-emitting diodes lamp and ear thermometer running.展开更多
Carbonaceous materials have drawn much attention in potassium-ion batteries (PIBs) due to their low price and superior physicochemical properties. However, the application of carbonaceous materials in PIB anodes is hi...Carbonaceous materials have drawn much attention in potassium-ion batteries (PIBs) due to their low price and superior physicochemical properties. However, the application of carbonaceous materials in PIB anodes is hindered by sluggish kinetics and large volume expansion. Herein, N/S co-doped carbon nanocapsule (NSCN) is constructed for superior K+ storage. The NSCN possesses 3D nanocapsule framework with abundant meso/macropores, which guarantees structural robustness and accelerates ions/electrons transportation. The high-level N/S co-doping in carbon matrix not only generates ample defects and active sites for K+ adsorption, but also expands interlayer distance for facile K+ intercalation/deintercalation. As a result, the NSCN electrode delivers a high reversible capacity (408 mAh g^(−1) at 0.05 A g^(−1)), outstanding rate capability (149 mAh g^(−1) at 5 A g^(−1)) and favorable cycle stability (150m Ah g^(−1) at 2 A g^(−1) after 2000 cycles). Ex situ TEM, Raman and XPS measurements demonstrate the excellent stability and reversibility of NSCN electrode during potassiation/depotassiation process. This work provides inspiration for the optimization of energy storage materials by structure and doping engineering.展开更多
Electro-oxidation of Ce （ Ⅲ ） to Ce （ Ⅳ ） in parallel plate flow type electrolyzer divided with cation exchange membrane was carried out in nitric acid media at carbon felt anode under galvanostatic conditions. ...Electro-oxidation of Ce （ Ⅲ ） to Ce （ Ⅳ ） in parallel plate flow type electrolyzer divided with cation exchange membrane was carried out in nitric acid media at carbon felt anode under galvanostatic conditions. Carbon felt was used as an anode for its high specific surface area and high oxygen evolution overpotential. Pt coated Ti plates were used as cathode and anode current feeder. The oxidation of 1 mol· L^-1 Ce（ Ⅲ ） solution in 2 mol· L^- 1 HNO3 was proceeding with a high current efficiency （92%） until about 80% of Ce（ Ⅲ ） was oxidized. Then, oxygen evolution, accompanied by terminal voltage jump, took place, lowering current efficiency. Ce（ Ⅲ ） was oxidized up to 90% with current efficiency of 62%. In this mode, strong carbon felt anode oxidation was observed. The wear out of carbon felt was 46% in six consequent runs （6 h of operation）. After each run, carbon felt surface had to be renewed with slightly alkaline solution to remove carbon oxidation products and ensure regular operational conditions. When anode surface was blocked, oxygen evolution took place from the beginning of electrolysis due to higher actual current density. The wear out of carbon felt anode could be minimized by means of oxygen evolution prevention. In the case when electrolysis had been stopped before oxygen evolution started （at Ce（ Ⅳ ） conversion of about 80% ）, the wear out of anode was less than 2% during 6 consequent runs （4 h of operation）.展开更多
Potassium-ion batteries(PIBs)are potential“Beyond Li-ion Batteries”candidates for their resource advantage and low standard electrode potential.To date,the research on PIBs is in its early stages,the most urgent tas...Potassium-ion batteries(PIBs)are potential“Beyond Li-ion Batteries”candidates for their resource advantage and low standard electrode potential.To date,the research on PIBs is in its early stages,the most urgent task is to develop high-performance electrode materials and reveal their potassium storage mechanism.For PIBs anode materials,carbon with tunable microstructure,excellent electrochemical activity,nontoxicity and low price is considered as one of the most promising anode materials for commercialization.Although some breakthrough works have emerged,the overall electrochemical performance of the reported carbon anode is still far away from practical application.Herein,we carry out a comprehensive overview of PIBs carbon anode in terms of three aspects of rational design of structure,performance evaluation criteria and characterization of potassium storage mechanism.First,the regulation mechanism of key structural features of carbon anode on its potassium storage performance and the representative structural regulation strategies are introduced.Then,in view of the undefined performance evaluation criteria of PIBs carbon anode,a reference principle for evaluating the potassium storage performance of carbon anode is proposed.Finally,the advanced characterization techniques for the potassium storage mechanism of carbon anode are summarize.This review aims to provide guidance for the development of practical PIBs anode.展开更多
In view of rich potassium resources and their working potential,potassium-ion batteries(PIBs)are deemed as next generation rechargeable batteries.Owing to carbon materials with the preponderance of durability and econ...In view of rich potassium resources and their working potential,potassium-ion batteries(PIBs)are deemed as next generation rechargeable batteries.Owing to carbon materials with the preponderance of durability and economic price,they are widely employed in PIBs anode materials.Currently,porosity design and heteroatom doping as efficacious improvement strategies have been applied to the structural design of carbon materials to improve their electrochemical performances.Herein,nitrogen-doped mesoporous carbon spheres(MCS)are synthesized by a facile hard template method.The MCS demonstrate larger interlayer spacing in a short range,high specific surface area,abundant mesoporous structures and active sites,enhancing K-ion migration and diffusion.Furthermore,we screen out the pyrolysis temperature of 900°C and the pore diameter of 7 nm as optimized conditions for MCS to improve performances.In detail,the optimized MCS-7-900 electrode achieves high rate capacity(107.9 mAh g^(−1) at 5000 mA g^(−1))and stably brings about 3600 cycles at 1000 mA g^(−1).According to electrochemical kinetic analysis,the capacitive-controlled effects play dominant roles in total storage mechanism.Additionally,the full-cell equipped MCS-7-900 as anode is successfully constructed to evaluate the practicality of MCS.展开更多
The anodic over voltage of the carbon anode in aluminumelectrolysis is of the order of 0.6 V at normal current densities.However, it can be reduced somewhat by doping the anode carbon withvarious inorganic compounds. ...The anodic over voltage of the carbon anode in aluminumelectrolysis is of the order of 0.6 V at normal current densities.However, it can be reduced somewhat by doping the anode carbon withvarious inorganic compounds. A new apparatus was designed to improvethe precision of over voltage measurements. Anodes were doped withMgAl_2O_4 and AlF_3 both by impregnation of the coke and by addingpowder, and the measured over voltage was compared with that ofUndoped samples. For prebake type anodes baked at around 1150 deg. C,the anodic overvoltage was reduced by 40-60 mV, And for Soderbergtype anodes, baked at 950 deg. C, by 60-80 mV.展开更多
基金Project(090302012)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(50934005)supported by the National Natural Science Foundation of China
文摘Laboratory-scale carbon anodes were produced by a new method of high temperature mould pressing, and their physico-chemical properties were studied. The influence of mould pressing conditions and coal pitch addition on the bulk density, crushing strength, and oxidation resistance was analyzed. The mierostructure of carbon anodes was investigated by scanning electron microscopy （SEM）, and the mechanism of producing carbon anodes by high-temperature mould pressing was analyzed. The results show that when the anodes are produced by high-temperature mould pressing, coal pitch can expand into the coke particles and fill the pores inside the particles, which is beneficial for improving the quality of prebaked anodes. The bulk density of carbon anodes is 1.64-1.66 g/cm3, which is 0.08-0.12 g/cm3 higher than that of industrial anodes, and the oxidation resistance of carbon anodes is also significantly improved.
基金supported by the National Natural Science Foundation of China(5197219862133007)the Taishan Scholars Program of Shandong Province(tsqn201812002,ts20190908)+1 种基金the Shenzhen Fundamental Research Program(JCYJ20190807093405503)The Natural Science Foundation of Shandong Province(No.ZR2020JQ19)。
文摘Silicon(Si)has been studied as a promising alloying type anode for lithium-ion batteries due to its high specific capacity,low operating potential and abundant resources.Nevertheless,huge volume expansion during alloying/dealloying processes and low electronic conductivity of Si anodes restrict their electrochemical performance.Thus,carbon(C)materials with special physical and chemical properties are applied in Si anodes to effectively solve these problems.This review focuses on current status in the exploration of Si/C anodes,including the lithiation mechanism and solid electrolyte interface formation,various carbon sources in Si/C anodes,such as traditional carbon sources(graphite,pitch,biomass),and novel carbon sources(MXene,graphene,MOFs-derived carbon,graphdiyne,etc.),as well as interfacial bonding modes of Si and C in the Si/C anodes.Finally,we summarize and prospect the selection of carbonaceous materials,structural design and interface control of Si/C anodes,and application of Si/C anodes in all-solid-state lithium-ion batteries and sodium-ion batteries et al.This review will help researchers in the design of novel Si/C anodes for rechargeable batteries.
基金supported by the National Key Research and Development Program of China(2021YFB2400200)the National Natural Science Foundation of China(52104313,22172117,52072298)the Scientific Research Program of Shaanxi Provincial Education Department(21JK0808)。
文摘The resourceful and inexpensive red phosphorus has emerged as a promising anode material of potassium-ion batteries(PIBs) for its large theoretical capacities and low redox potentials in the multielectron alloying/dealloying reactions,yet chronically suffering from the huge volume expansion/shrinkage with a sluggish reaction kinetics and an unsatisfactory interfacial stability against volatile electrolytes.Herein,we systematically developed a series of localized high-concentration electrolytes(LHCE) through diluting high-concentration ether electrolytes with a non-solvating fluorinated ether to regulate the formation/evolution of solid electrolyte interphases(SEI) on phosphorus/carbon(P/C) anodes for PIBs.Benefitting from the improved mechanical strength and structural stability of a robust/uniform SEI thin layer derived from a composition-optimized LHCE featured with a unique solvation structure and a superior K+migration capability,the P/C anode with noticeable pseudocapacitive behaviors could achieve a large reversible capacity of 760 mA h g^(-1)at 100 mA g^(-1),a remarkable capacity retention rate of 92.6% over 200 cycles at 800 mA g^(-1),and an exceptional rate capability of 334 mA h g^(-1)at8000 mA g^(-1).Critically,a suppressed reduction of ether solvents with a preferential decomposition of potassium salts in anion-derived interfacial reactions on P/C anode for LHCE could enable a rational construction of an outer organic-rich and inner inorganic-dominant SEI thin film with remarkable mechanical strength/flexibility to buffer huge volume variations and abundant K+diffusion channels to accelerate reaction kinetics.Additionally,the highly reversible/durable full PIBs coupling P/C anodes with annealed organic cathodes further verified an excellent practical applicability of LHCE.This encouraging work on electrolytes regulating SEI formation/evolution would advance the development of P/C anodes for high-performance PIBs.
基金financially supported by the Beijing Municipal Science and Technology Commission(Grant No.Z181100004718007)the National Key R&D Program of China(Grant No.2017YFB0102204)。
文摘Sodium-ion batteries(SIBs)have attracted significant attentions as promising alternatives to lithium-ion batteries for large-scale energy storage applications.Here carbon materials are considered as the most competitive anodes for SIBs based on their low-cost,abundant availability and excellent structural stability.Pitch,with high carbon content and low cost,is an ideal raw precursor to prepare carbon materials for large-scale applications.Nevertheless,the microstructures of pitch-based carbon are highly ordered with smaller interlayer distances,which are unfavorable for Na ion storage.Many efforts have been made to improve the sodium storage performance of pitch-based carbon materials.This review summarizes the recent progress about the application of pitch-based carbons for SIBs anodes in the context of carbon’s morphology and structure regulation strategies,including morphology adjustment,heteroatoms doping,fabricating heterostructures,and the increase of the degree of disorder.Besides,the advantages,present challenges,and possible solutions to current issues in pitch-based carbon anode are discussed,with the highlight of future research directions.This review will provide a deep insight into the development of low-cost and high-performance pitch-based carbon anode for SIBs.
文摘Biomass-derived hard carbons,usually prepared by pyrolysis,are widely considered the most promising anode materials for sodium-ion bat-teries(SIBs)due to their high capacity,low poten-tial,sustainability,cost-effectiveness,and environ-mental friendliness.The pyrolysis method affects the microstructure of the material,and ultimately its so-dium storage performance.Our previous work has shown that pyrolysis in a sealed graphite vessel im-proved the sodium storage performance of the car-bon,however the changes in its microstructure and the way this influences the sodium storage are still unclear.A series of hard carbon materials derived from corncobs(CCG-T,where T is the pyrolysis temperature)were pyrolyzed in a sealed graphite vessel at different temperatures.As the pyrolysis temperature increased from 1000 to 1400℃ small carbon domains gradually transformed into long and curved domains.At the same time,a greater number of large open pores with uniform apertures,as well as more closed pores,were formed.With the further increase of pyrolysis temperature to 1600℃,the long and curved domains became longer and straighter,and some closed pores gradually became open.CCG-1400,with abundant closed pores,had a superior SIB performance,with an initial reversible ca-pacity of 320.73 mAh g^(-1) at a current density of 30 mA g^(-1),an initial Coulomb efficiency(ICE)of 84.34%,and a capacity re-tention of 96.70%after 100 cycles.This study provides a method for the precise regulation of the microcrystalline and pore structures of hard carbon materials.
基金National Key R&D Program of China,Grant/Award Number:2023YFB2503900National Natural Science Foundation of China,Grant/Award Number:12172143Shenzhen Science and Technology Program,Grant/Award Numbers:JCYJ20220818100418040,JCYJ20220530160816038。
文摘Constructing silicon(Si)-based composite electrodes that possess high energy density,long cycle life,and fast charging capability simultaneously is critical for the development of high performance lithium-ion batteries for mitigating range anxiety and slow charging issues in new energy vehicles.Herein,a thick silicon/carbon composite electrode with vertically aligned channels in the thickness direction(VC-SC)is constructed by employing a bubble formation method.Both experimental characterizations and theoretical simulations confirm that the obtained vertical channel structure can effectively address the problem of sluggish ion transport caused by high tortuosity in conventional thick electrodes,conspicuously enhance reaction kinetics,reduce polarization and side reactions,mitigate stress,increase the utilization of active materials,and promote cycling stability of the thick electrode.Consequently,when paired with LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622),the VC-SC||NCM622 pouch type full cell(~6.0 mAh cm^(-2))exhibits significantly improved rate performance and capacity retention compared with the SC||NCM622 full cell with the conventional silicon/carbon composite electrode without channels(SC)as the anode.The assembled VC-SC||NCM622 pouch full cell with a high energy density of 490.3 Wh kg^(-1)also reveals a remarkable fast charging capability at a high current density of 2.0 mA cm^(-2),with a capacity retention of 72.0%after 500 cycles.
基金financially supported by the National Natural Science Foundation of China(22209057)the Guangzhou Basic and Applied Basic Research Foundation(2024A04J0839)。
文摘Carbon-based materials are recognized as anodes fulling of promise for potassium ion batteries(PIBs)due to advantages of affordable cost and high conductivity.However,they still face challenges including structural unstability and slow kinetics.It is difficult to achieve efficient potassium storage with unmodified carbonaceous anode.Herein,atomic bismuth(Bi)sites with different atom coordinations anchored on carbon nanosheets(CNSs)have been synthesized through a template method.The properties of prepared multi-doping carbon anodes Bi-N_(3)S_(1)/CNSs,Bi-N_(3)P_(1)/CNSs and Bi-N_(4)/CNSs were probed in PIBs.The configuration Bi-N_(3)S_(1) with stronger charge asymmetry exhibits superior potassium storage performance compared to Bi-N_(3)P_(1) and Bi-N_(4) configurations.The Bi-N_(3)S_(1)/CNSs display a rate capacity of 129.2 mAh g^(-1)even at 10 A g^(-1)and an impressive cyclability characterized by over 5000 cycles at 5 A g^(-1),on account of its optimal coordination environment with more active Bi centers and K^(+)adsorption sites.Notably,assembled potassium-ion full cell Mg-KVO//Bi-N_(3)S_(1)/CNSs also shows an outstanding cycling stability,enduring 3000 cycles at 2 A g^(-1).Therefore,it can be demonstrated that regulating the electronic structure of metallic centre M-N_(4) via changing the type of ligating atom is a feasible strategy for modifying carbon anodes,on the base of co-doping metal and non-metal.
基金supported by the National Natural Science Foundation of China(Nos.52071171,52202248,22208138)Natural Science Foundation of Liaoning Province(2020-MS-137,2023-MS-140)+7 种基金Doctoral Start-up Foundation of Liaoning Province,China(2020-BS-081)Australian Research Council(ARC)through Future Fellowship(FT210100298,FT210100806)Discovery Project(DP220100603)Linkage Project(LP210100467,LP210200504,LP210200345,LP220100088)Industrial Transformation Training center(IC180100005)schemesCSIRO Energy center and Kick-Start Project,and the Australian Government through the Cooperative Research Centres Projects(CRCPXIII000077)Young Scientific Project of the Department of Education of Liaoning Province(LJKQZ20222263,LQN202008)Anhui Province Key Laboratory of Coal Clean Conversion and High Valued Utilization,Anhui University of Technology(CHV22-05).
文摘Red phosphorus has been well-recognized as promising anode materials for lithium-ion batteries(LIBs)and potassium-ion batteries(PIBs)due to its extremely high theoretical capacity and low cost.However,the huge volume change and poor electric conductivity severely limit its further practical application.Herein,the nanoscale ultrafine red phosphorus has been successfully confined in a three-dimensional pitch-based porous carbon skeleton composed of well-interconnected carbon nanosheets through the vaporization-condensation method.Except for the traditional requirement of high electric conductivity and stable mechanical stability,the micropores and small mesopores in the porous carbon matrix centered at 1 to 3 nm and the abundant amount of oxygen-containing functional groups are also beneficial for the high loading and dispersion of red phosphorus.As anode for LIBs,the composite exhibits high reversible discharge capacities of 968 mAh g^(-1),excellent rate capabilities of 593 mAh g^(-1)at 2 A g^(-1),and long cycle performance of 557 mAh g^(-1)at 2 A g^(-1).More impressively,as the anode for PIBs,the composite presents a high reversible capacity of 661 mAh g^(-1)and a stable capacity of 312 mAh g^(-1)at 0.5 A g^(-1)for 500 cycles with a capacity retention up to 84.3%.This work not only sheds light on the structure design of carbon hosts with specific pore structure but also open an avenue for high value-added utilization of coal tar pitch.
基金supported by the National Natural Science Foundation of China(Nos.52031008,51874211,21673162,51325102,U22B2071)the International Science and Technology Cooperation Program of China(No.2015DFA90750)the China Postdoctoral Science Foundation(No.2020M682468)。
文摘The corrosion inhibition efficacy of titanate(CaTiO_(3))for carbon anodes in molten salts was investigated through various analytical techniques,including linear sweep voltammetry,X-ray diffraction,scanning electron microscopy,and energy dispersion spectroscopy.The results demonstrate that the addition of CaTiO_(3)corrosion inhibitor efficiently passivates the carbon anode and leads to the formation of a dense CaTiO_(3)layer during the electrolysis process in molten CaCl_(2)-CaO.Subsequently,the passivated carbon anode effectively undergoes the oxygen evolution reaction,with an optimal current density for passivation identified at 400 m A/cm^(2).Comprehensive investigations,including CaTiO_(3)solubility tests in molten CaCl_(2)-CaO and numerical modeling of the stability of complex ionic structures,provide compelling evidence supporting“complexation-precipitation”passivation mechanism.This mechanism involves the initial formation of a complex containing TiO_(2)·nCaO by CaTiO_(3)and CaO,which subsequently decomposes to yield CaTiO_(3),firmly coating the surface of the carbon anode.In practical applications,the integration of CaTiO_(3)corrosion inhibitor with the carbon anode leads to the successful preparation of the FeCoNiCrMn high-entropy alloy without carbon contamination in the molten CaCl_(2)-CaO.
文摘Recent technological advancements,such as portable electronics and electric vehicles,have created a pressing need for more efficient energy storage solutions.Lithium-ion batteries(LIBs)have been the preferred choice for these applications,with graphite being the standard anode material due to its stability.However,graphite falls short of meeting the growing demand for higher energy density,possessing a theoretical capacity that lags behind.To address this,researchers are actively seeking alternative materials to replace graphite in commercial batteries.One promising avenue involves lithiumalloying materials like silicon and phosphorus,which offer high theoretical capacities.Carbon-silicon composites have emerged as a viable option,showing improved capacity and performance over traditional graphite or pure silicon anodes.Yet,the existing methods for synthesizing these composites remain complex,energy-intensive,and costly,preventing widespread adoption.A groundbreaking approach is presented here:the use of a laser writing strategy to rapidly transform common organic carbon precursors and silicon blends into efficient“graphenic silicon”composite thin films.These films exhibit exceptional structural and energy storage properties.The resulting three-dimensional porous composite anodes showcase impressive attributes,including ultrahigh silicon content,remarkable cyclic stability(over 4500 cycles with∼40%retention),rapid charging rates(up to 10 A g^(-1)),substantial areal capacity(>5.1 mAh cm^(-2)),and excellent gravimetric capacity(>2400 mAh g^(-1) at 0.2 A g^(-1)).This strategy marks a significant step toward the scalable production of high-performance LIB materials.Leveraging widely available,cost-effective precursors,the laser-printed“graphenic silicon”composites demonstrate unparalleled performance,potentially streamlining anode production while maintaining exceptional capabilities.This innovation not only paves the way for advanced LIBs but also sets a precedent for transforming various materials into high-performing electrodes,promising reduced complexity and cost in battery production.
基金Financial support from the National Natural Science Foundation of China (22075320)。
文摘To achieve high energy density in lithium batteries,the construction of lithium-ion/metal hybrid anodes is a promising strategy.In particular,because of the anisotropy of graphite,hybrid anode formed by graphite/Li metal has low transport kinetics and is easy to causes the growth of lithium dendrites and accumulation of dead Li,which seriously affects the cycle life of batteries and even causes safety problems.Here,by comparing graphite with two types of hard carbon,it was found that hybrid anode formed by hard carbon and lithium metal,possessing more disordered mesoporous structure and lithophilic groups,presents better performance.Results indicate that the mesoporous structure provides abundant active site and storage space for dead lithium.With the synergistic effect of this structure and lithophilic functional groups(–COOH),the reversibility of hard carbon/lithium metal hybrid anode is maintained,promoting uniform deposition of lithium metal and alleviating formation of lithium dendrites.The hybrid anode maintains a 99.5%Coulombic efficiency(CE)after 260 cycles at a specific capacity of 500 m Ah/g.This work provides new insights into the hybrid anodes formed by carbon-based materials and lithium metal with high specific energy and fast charging ability.
基金supported by the National Natural Science Foundation of China(grant nos.21975026 and 22005033)the National Postdoctoral Program of China(no.BX20180037)+1 种基金China Postdoctoral Science Foundation(no.2018M640077)the Beijing Institute of Technology Research Fund Program for Young Scholars(no.XSQD-202108005).
文摘Developing effective strategies to improve the initial Coulombic efficiency(ICE)and cycling stability of hard carbon(HC)anodes for sodium-ion batteries is the key to promoting the commercial application of HC.In this paper,homotype heterojunctions are designed on HC to induce the generation of stable solid electrolyte interfaces,which can effectively increase the ICE of HC from 64.7%to 81.1%.The results show that using a simple surface engineering strategy to construct a homotypic amorphous Al_(2)O_(3) layer on the HC could shield the active sites,and further inhibit electrolyte decomposition and side effects occurrence.Particularly,due to the suppression of continuous decomposition of NaPF 6 in ester-based electrolytes,the accumulation of NaF could be reduced,leading to the formation of thinner and denser solid electrolyte interface films and a decrease in the interface resistance.The HC anode can not only improve the ICE but elevate its sodium storage performance based on this homotype heterojunction composed of HC and Al_(2)O_(3).The optimized HC anode exhibits an outstanding reversible capacity of 321.5mAhg^(−1) at 50mAg^(−1).The cycling stability is also improved effectively,and the capacity retention rate is 86.9%after 2000 cycles at 1Ag^(−1) while that of the untreated HC is only 52.6%.More importantly,the improved sodium storage behaviors are explained by electrochemical kinetic analysis.
基金Project (09001232) supported by the Doctoral Foundation of Henan University of Science and Technology,China
文摘Based on the hexagonal crystallite model of graphite,the electrochemical characteristics of carbon atoms on the edge and basal plane were proposed by analyzing graphite crystal structure and bonds of carbon atoms in different sites.A spherical close-packed model for graphite particle was developed.The fractions of surface carbon atoms（SCA） and edge carbon atoms（ECA） were derived in the expression of crystallographic parameters and particle size,and the effects of ECA on the initial irreversible capacity and the mechanisms of action were analyzed and verified.The results show that the atoms on the edge are more active for electrochemical reactions,such as electrolyte decomposition and tendency to form stable bond with other atoms and groups.For the practical graphite particle,corresponding modifying factors were introduced to revise the difference in calculating results.The revised expression is suitable for the calculation of the fractions of SCA and ECA for carbon materials such as graphite,disordered carbon and modified graphite.
基金Singapore MOE Tier Ⅱ grant R143-000-A29-112the National Research Foundation under the Grant of NRF2017NRF-NSFC001-007.
文摘Pore structure of hard carbon has a fundamental influence on the electrochemical properties in sodium-ion batteries(SIBs).Ultra-micropores(<0.5 nm)of hard carbon can function as ionic sieves to reduce the diffusion of slovated Na+but allow the entrance of naked Na^(+) into the pores,which can reduce the interficial contact between the electrolyte and the inner pores without sacrificing the fast diffusion kinetics.Herein,a molten diffusion-carbonization method is proposed to transform the micropores(>1 nm)inside carbon into ultra-micropores(<0.5 nm).Consequently,the designed carbon anode displays an enhanced capacity of 346 mAh g^(−1) at 30 mA g^(−1) with a high ICE value of~80.6%and most of the capacity(~90%)is below 1 V.Moreover,the high-loading electrode(~19 mg cm^(−2))exhibits a good temperature endurance with a high areal capacity of 6.14 mAh cm^(−2) at 25℃ and 5.32 mAh cm^(−2) at −20℃.Based on the in situ X-ray diffraction and ex situ solid-state nuclear magnetic resonance results,the designed ultra-micropores provide the extra Na+storage sites,which mainly contributes to the enhanced capacity.This proposed strategy shows a good potential for the development of high-performance SIBs.
基金financially supported by the National Natural Science Foundation of China(Nos.21872045 and 21975069)the Key Project of Research and Development Plan of Hunan Province(Grant 2019SK2071)+1 种基金the Natural Science Foundation of Hunan Province(2020JJ4169)support from the Development and Reform Commission of Hunan Province.
文摘Studies have found that oxygen-rich-containing functional groups in carbon-based materials can be used as active sites for the storage performance of K^(+),but the basic storage mechanism is still unclear.Herein,we construct and optimize 3D honeycomb-like carbon grafted with plentiful COOH/C=O functional groups(OFGC)as anodes for potassium ion batteries.The OFGC electrode with steady structure and rich functional groups can effectively contribute to the capacity enhancement and the formation of stable solid electrolyte interphase(SEI)film,achieving a high reversible capacity of 230 mAh g^(-1) at 3000 mA g^(-1) after 10,000 cycles(almost no capacity decay)and an ultra-long cycle time over 18 months at 100 mA g^(-1).The study results revealed the reversible storage mechanism between K^(+)and COOH/C=O functional groups by forming C-O-K compounds.Meanwhile,the in situ electrochemical impedance spectroscopy proved the highly reversible and rapid de/intercalation kinetics of K+in the OFGC electrode,and the growth process of SEI films.In particular,the full cells assembled by Prussian blue cathode exhibit a high energy density of 113 Wh kg^(-1) after 800 cycles(calculated by the total mass of anode and cathode),and get the light-emitting diodes lamp and ear thermometer running.
基金the financial supports from the National Natural Science Foundation of China(Grant Nos.51872005,U1508201,52072002)。
文摘Carbonaceous materials have drawn much attention in potassium-ion batteries (PIBs) due to their low price and superior physicochemical properties. However, the application of carbonaceous materials in PIB anodes is hindered by sluggish kinetics and large volume expansion. Herein, N/S co-doped carbon nanocapsule (NSCN) is constructed for superior K+ storage. The NSCN possesses 3D nanocapsule framework with abundant meso/macropores, which guarantees structural robustness and accelerates ions/electrons transportation. The high-level N/S co-doping in carbon matrix not only generates ample defects and active sites for K+ adsorption, but also expands interlayer distance for facile K+ intercalation/deintercalation. As a result, the NSCN electrode delivers a high reversible capacity (408 mAh g^(−1) at 0.05 A g^(−1)), outstanding rate capability (149 mAh g^(−1) at 5 A g^(−1)) and favorable cycle stability (150m Ah g^(−1) at 2 A g^(−1) after 2000 cycles). Ex situ TEM, Raman and XPS measurements demonstrate the excellent stability and reversibility of NSCN electrode during potassiation/depotassiation process. This work provides inspiration for the optimization of energy storage materials by structure and doping engineering.
文摘Electro-oxidation of Ce （ Ⅲ ） to Ce （ Ⅳ ） in parallel plate flow type electrolyzer divided with cation exchange membrane was carried out in nitric acid media at carbon felt anode under galvanostatic conditions. Carbon felt was used as an anode for its high specific surface area and high oxygen evolution overpotential. Pt coated Ti plates were used as cathode and anode current feeder. The oxidation of 1 mol· L^-1 Ce（ Ⅲ ） solution in 2 mol· L^- 1 HNO3 was proceeding with a high current efficiency （92%） until about 80% of Ce（ Ⅲ ） was oxidized. Then, oxygen evolution, accompanied by terminal voltage jump, took place, lowering current efficiency. Ce（ Ⅲ ） was oxidized up to 90% with current efficiency of 62%. In this mode, strong carbon felt anode oxidation was observed. The wear out of carbon felt was 46% in six consequent runs （6 h of operation）. After each run, carbon felt surface had to be renewed with slightly alkaline solution to remove carbon oxidation products and ensure regular operational conditions. When anode surface was blocked, oxygen evolution took place from the beginning of electrolysis due to higher actual current density. The wear out of carbon felt anode could be minimized by means of oxygen evolution prevention. In the case when electrolysis had been stopped before oxygen evolution started （at Ce（ Ⅳ ） conversion of about 80% ）, the wear out of anode was less than 2% during 6 consequent runs （4 h of operation）.
基金supported financially by the National Key Research and Development Program of China (Grants No. 2017YFA0206301)the National Natural Science Foundation of China (Grants No. 51631001 and 51631001)the China-Germany Collaboration Project (Grants No. M-0199)
文摘Potassium-ion batteries(PIBs)are potential“Beyond Li-ion Batteries”candidates for their resource advantage and low standard electrode potential.To date,the research on PIBs is in its early stages,the most urgent task is to develop high-performance electrode materials and reveal their potassium storage mechanism.For PIBs anode materials,carbon with tunable microstructure,excellent electrochemical activity,nontoxicity and low price is considered as one of the most promising anode materials for commercialization.Although some breakthrough works have emerged,the overall electrochemical performance of the reported carbon anode is still far away from practical application.Herein,we carry out a comprehensive overview of PIBs carbon anode in terms of three aspects of rational design of structure,performance evaluation criteria and characterization of potassium storage mechanism.First,the regulation mechanism of key structural features of carbon anode on its potassium storage performance and the representative structural regulation strategies are introduced.Then,in view of the undefined performance evaluation criteria of PIBs carbon anode,a reference principle for evaluating the potassium storage performance of carbon anode is proposed.Finally,the advanced characterization techniques for the potassium storage mechanism of carbon anode are summarize.This review aims to provide guidance for the development of practical PIBs anode.
基金This work was financially supported by the Start-up Funding of Jinan University(88016105 and 55800001)the discipline construction outstanding young backbone project(12819023)+1 种基金the Fundamental Research Funds for the Central Universities(21620317)the Guangdong Basic and Applied Basic Research Foundation(2020A1515110611 and 2021A1515010362).
文摘In view of rich potassium resources and their working potential,potassium-ion batteries(PIBs)are deemed as next generation rechargeable batteries.Owing to carbon materials with the preponderance of durability and economic price,they are widely employed in PIBs anode materials.Currently,porosity design and heteroatom doping as efficacious improvement strategies have been applied to the structural design of carbon materials to improve their electrochemical performances.Herein,nitrogen-doped mesoporous carbon spheres(MCS)are synthesized by a facile hard template method.The MCS demonstrate larger interlayer spacing in a short range,high specific surface area,abundant mesoporous structures and active sites,enhancing K-ion migration and diffusion.Furthermore,we screen out the pyrolysis temperature of 900°C and the pore diameter of 7 nm as optimized conditions for MCS to improve performances.In detail,the optimized MCS-7-900 electrode achieves high rate capacity(107.9 mAh g^(−1) at 5000 mA g^(−1))and stably brings about 3600 cycles at 1000 mA g^(−1).According to electrochemical kinetic analysis,the capacitive-controlled effects play dominant roles in total storage mechanism.Additionally,the full-cell equipped MCS-7-900 as anode is successfully constructed to evaluate the practicality of MCS.
基金the Norwegian Aluminium Industry, the Norwegian Research Council and the China National Key Fundamental Research Development Project (No.G1999064903)
文摘The anodic over voltage of the carbon anode in aluminumelectrolysis is of the order of 0.6 V at normal current densities.However, it can be reduced somewhat by doping the anode carbon withvarious inorganic compounds. A new apparatus was designed to improvethe precision of over voltage measurements. Anodes were doped withMgAl_2O_4 and AlF_3 both by impregnation of the coke and by addingpowder, and the measured over voltage was compared with that ofUndoped samples. For prebake type anodes baked at around 1150 deg. C,the anodic overvoltage was reduced by 40-60 mV, And for Soderbergtype anodes, baked at 950 deg. C, by 60-80 mV.
