In this work,we have applied molybdenum(Mo)and titanium(Ti)co-doping to solve the degradation of Ni-rich cathodes.The modified cathode,i.e.,Li(Ni_(0.89)Co_(0.05)Mn_(0.05)Mo_(0.005)Ti_(0.005))O_(2) holds a stable struc...In this work,we have applied molybdenum(Mo)and titanium(Ti)co-doping to solve the degradation of Ni-rich cathodes.The modified cathode,i.e.,Li(Ni_(0.89)Co_(0.05)Mn_(0.05)Mo_(0.005)Ti_(0.005))O_(2) holds a stable structure with expanded crystal lattice distance which improves Li ion diffusion kinetics.The dopants have suppressed the growth of primary particles,formed a coating on the surface,and promoted the elongated morphology.Moreover,the mechanical strength of these particles has increased,as confirmed by the nanoindentation test,which can help suppress particle cracking.The detrimental H2-H3 phase transition has been postponed by 90 mV allowing the cathode to operate at a higher voltage.A better cycling stability over 100 cycles with 69%capacity retention has been observed.We believe this work points out a way to improve the cycling performance,Coulombic efficiency and capacity retention in Ni-rich cathodes.展开更多
Wide-bandgap two-dimensional (2D) β-TeO_(2) has been reported as a high-mobility p-type transparent semiconductor [Nat. Electron. 4 277 (2021)], attracting significant attention. This "breakthrough" not onl...Wide-bandgap two-dimensional (2D) β-TeO_(2) has been reported as a high-mobility p-type transparent semiconductor [Nat. Electron. 4 277 (2021)], attracting significant attention. This "breakthrough" not only challenges the conventional characterization of TeO_(2) as an insulator but also conflicts with the anticipated difficulty in hole doping of TeO_(2) by established chemical trends. Notably, the reported Fermi level of 0.9 eV above the valence band maximum actually suggests that the material is an insulator, contradicting the high hole density obtained by Hall effect measurement. Furthermore, the detected residual Se and the possible reduced elemental Te in the 2D β-TeO_(2) samples introduces complexity, considering that elemental Se, Te, and Te_(1−x)Se_(x) themselves are high-mobility p-type semiconductors. Therefore, doubts regarding the true cause of the p-type conductivity observed in the 2D β-TeO_(2) samples arise. In this Letter, we employ density functional theory calculations to illustrate that TeO_(2), whether in its bulk forms of α-, β-, or γ-TeO_(2), or in the 2D β-TeO_(2) nanosheets, inherently exhibits insulating properties and poses challenges in carrier doping due to its shallow conduction band minimum and deep valence band maximum. Our findings shed light on the insulating properties and doping difficulty of TeO_(2), contrasting with the claimed p-type conductivity in the 2D β-TeO_(2) samples, prompting inquiries into the true origin of the p-type conductivity.展开更多
Despite sulfurization offers the advantage of improving the photovoltaic performance in preparing Cu(In,Ga)Se2(CIGS)absorbers,deep level defects in the absorber and poor energy level alignment on the front surface are...Despite sulfurization offers the advantage of improving the photovoltaic performance in preparing Cu(In,Ga)Se2(CIGS)absorbers,deep level defects in the absorber and poor energy level alignment on the front surface are still main obstacles limiting the improvement of power co nversion efficiency(PCE)in sulfided CIGS solar cells.Herein,an in-situ Na doping strategy is proposed,in which the tailing effect of crystal growth is used to promote the sulfurization of CIGS absorbers.It is found that the grain growth is supported by Na incorporating due to the enrichment of NaSe_(x)near the upper surface.The high soluble Na during grain growth can not only suppress intrinsic In_(Cu) donor defects in the absorber,but also tailor S distribution in bulk and the band alignment at the heterojunction,which are both beneficial for the effective electron carriers.Meanwhile,the Na aggregation near the bottom of the absorber also contributes to the crystalline quality increasing and favorable ultra-thin MoSe_(2) formation at back contact,resulting in a reduced barrier height conducive to hole transport.PCE of the champion device is as high as 16.76%with a 28%increase.This research offers new insights into synthesizing CIGS solar cells and other chalcogenide solar cells with superior cell performance when using an intense sulfurization process.展开更多
Solution-processed Cu(In,Ga)Se_(2)(CIGS) solar cells suffer from serious carrier recombination and power conversion efficiency(PCE) loss because of the poor film properties and easy formation of defects.Herein, we pro...Solution-processed Cu(In,Ga)Se_(2)(CIGS) solar cells suffer from serious carrier recombination and power conversion efficiency(PCE) loss because of the poor film properties and easy formation of defects.Herein, we propose Ag&Se co-selenization strategy to enhance the crystallization and passivate harmful defects of the CIGS films. The formation of Ag-Se phase during the selenization process enables the formation of large grains and suppresses the deep level defects. It is found that Ag doping can enlarge the depletion region width, lower the Urbach energy and prolong the carrier lifetime. As a result, a champion solution-processed CIGS solar cell presents a high efficiency of 16.48% with the highly improved opencircuit voltage(VOC) of 662 m V and fill factor(FF) of 75.8%. This work provides an efficient strategy to prepare high quality solution-processed CIGS films for high-performance CIGS solar cells.展开更多
Ti at the oxidation states of Ti^(3+)and Ti^(4+),was used to enhance the performance of Na_(3)V_(2)(PO_(4))_(2)F_(2)O by partially substituting vanadium.After doping Ti,the crystallographic volume is decreased due to ...Ti at the oxidation states of Ti^(3+)and Ti^(4+),was used to enhance the performance of Na_(3)V_(2)(PO_(4))_(2)F_(2)O by partially substituting vanadium.After doping Ti,the crystallographic volume is decreased due to the less radii of Ti^(3+/4+),and the valence of Ti is demonstrated identical to V.During sodium insertion in Ti-doped Na_(3)V_(2)(PO_(4))_(2)F_(2)O,the two discharge plateaus split into three because of the rearrangement of local redox environment.Consequently,the optimized Na_(3)V_(0.96)Ti_(0.04)(PO_(4))_(2)F_(2)O shows a specific capacity of 123 and 63 mA·h/g at 0.1C and 20C,respectively.After 350 cycles at 0.5C,the capacity is gradually reduced corresponding to a retention of 71.05%.The significantly improved performance is attributed to the rapid electrochemical kinetics,and showcases the strategy of replacing V^(3+/4+)with Ti^(3+/4+)for high-performance vanadium-based oxyfluorophosphates.展开更多
Seawater electrolysis is a promising approach for sustainable energy without relying on precious freshwater.However,the large-scale seawater electrolysis is hindered by low catalytic efficiency and severe anode corros...Seawater electrolysis is a promising approach for sustainable energy without relying on precious freshwater.However,the large-scale seawater electrolysis is hindered by low catalytic efficiency and severe anode corrosion caused by the harmful chlorine.In contrast to the oxygen evolution reaction (OER)and chlorin ion oxidation reaction (ClOR),glycerol oxidation reaction (GOR) is more thermodynamically and kinetically favorable alternative.Herein,a Ru doping cobalt phosphide (Ru-CoP_(2)) is proposed as a robust bifunctional electrocatalyst for seawater electrolysis and GOR,for the concurrent productions of hydrogen and value-added formate.The in situ and ex situ characterization analyses demonstrated that Ru doping featured in the dynamic reconstruction process from Ru-CoP_(2)to Ru-CoOOH,accounting for the superior GOR performance.Further coupling GOR with hydrogen evolution was realized by employing Ru-CoP_(2)as both anode and cathode,requiring only a low voltage of 1.43 V at 100 mA cm^(-2),which was 250 m V lower than that in alkaline seawater.This work guides the design of bifunctional electrocatalysts for energy-efficient seawater electrolysis coupled with biomass resource upcycling.展开更多
Hard carbon (HC) has been considered as promising anode material for sodium-ion batteries (SIBs).The optimization of hard carbon’s microstructure and solid electrolyte interface (SEI) property are demonstrated effect...Hard carbon (HC) has been considered as promising anode material for sodium-ion batteries (SIBs).The optimization of hard carbon’s microstructure and solid electrolyte interface (SEI) property are demonstrated effective in enhancing the Na+storage capability,however,a one-step regulation strategy to achieve simultaneous multi-scale structures optimization is highly desirable.Herein,we have systematically investigated the effects of boron doping on hard carbon’s microstructure and interface chemistry.A variety of structure characterizations show that appropriate amount of boron doping can increase the size of closed pores via rearrangement of carbon layers with improved graphitization degree,which provides more Na+storage sites.In-situ Fourier transform infrared spectroscopy/electrochemical impedance spectroscopy (FTIR/EIS) and X-ray photoelectron spectroscopy (XPS) analysis demonstrate the presence of more BC3and less B–C–O structures that result in enhanced ion diffusion kinetics and the formation of inorganic rich and robust SEI,which leads to facilitated charge transfer and excellent rate performance.As a result,the hard carbon anode with optimized boron doping content exhibits enhanced rate and cycling performance.In general,this work unravels the critical role of boron doping in optimizing the pore structure,interface chemistry and diffusion kinetics of hard carbon,which enables rational design of sodium-ion battery anode with enhanced Na+storage performance.展开更多
The past decade has witnessed the rapid increasement in power conversion efficiency of perovskite solar cells(PSCs).However,serious ion migration hampers their operational stability.Although dopants composed of varied...The past decade has witnessed the rapid increasement in power conversion efficiency of perovskite solar cells(PSCs).However,serious ion migration hampers their operational stability.Although dopants composed of varied cations and anions are introduced into perovskite to suppress ion migration,the impact of cations or anions is not individually explored,which hinders the evaluation of different cations and further application of doping strategy.Here we report that a special group of sulfonic anions(like CF_(3)SO_(3)^(-))successfully introduce alkaline earth ions(like Ca^(2+))into perovskite lattice compared to its halide counterparts.Furthermore,with effective crystallization regulation and defect passivation of sulfonic anions,perovskite with Ca(CF_(3)SO_(3))_(2)shows reduced PbI2 residue and metallic Pb0 defects;thereby,corresponding PSCs show an enhanced PCE of 24.95%.Finally by comparing the properties of perovskite with Ca(CF_(3)SO_(3))_(2)and FACF_(3)SO_(3),we found that doped Ca^(2+)significantly suppressed halide migration with an activation energy of 1.246 eV which accounts for the improved operational stability of Ca(CF_(3)SO_(3))_(2-)doped PSCs,while no obvious impact of Ca^(2+)on trap density is observed.Combining the benefits of cations and anions,this study presents an effective method to decouple the effects of cations and anions and fabricate efficient and stable PSCs.展开更多
Black-phosphorus-structured nitrogen(BP-N)is an attractive high-energy-density material.However,high-pressure-synthesized BP-N will decompose at low pressure and cannot be quenched to ambient conditions.Finding a meth...Black-phosphorus-structured nitrogen(BP-N)is an attractive high-energy-density material.However,high-pressure-synthesized BP-N will decompose at low pressure and cannot be quenched to ambient conditions.Finding a method to stabilize it at 0 GPa is of great significance for its practical applications.However,unlike cubic gauche,layered polymeric,and hexagonal layered polymeric nitrogen(cg-N,LP-N,and HLP-N),it is always a metastable phase at high pressures up to 260 GPa,and decomposes into chains at 23 GPa.Here,on the basis of firstprinciples simulations,we find that P-atom doping can effectively reduce the synthesis pressure of BP-N and maintain its stability at 0 GPa.Uniform distribution of P-atom dopants within BP-N layers helps maintain the structural stability of these layers at 0 GPa,while interlayer electrostatic interaction induced by N-P dipoles enhances dynamic stability by eliminating interlayer slipping.Furthermore,pressure is conducive to enhancing the stability of BP-N and its doped forms by suppressing N-chain dissociation.For a configuration with 12.5%doping concentration,a gravimetric energy density of 8.07 kJ/g can be realized,which is nearly twice that of trinitrotoluene.展开更多
The Fe_(1−x)Ni_(x)VO_(4)(x=0,0.05,0.10,and 0.20)nanoparticles in this work were successfully synthesized via a co-precipitation method.The structural,magnetic and electrochemical properties of the prepared Fe_(1−x)Ni_...The Fe_(1−x)Ni_(x)VO_(4)(x=0,0.05,0.10,and 0.20)nanoparticles in this work were successfully synthesized via a co-precipitation method.The structural,magnetic and electrochemical properties of the prepared Fe_(1−x)Ni_(x)VO_(4) nanoparticles were studied as a function of Ni content.The experimental results show that the prepared Ni-doped FeVO_(4) samples have a triclinic structure.Scanning electron microscopy(SEM)images reveal a decrease in average nanoparticle size with increasing Ni content,leading to an enhancement in both specific surface area and magnetization values.X-ray absorption near edge structure(XANES)analysis confirms the substitution of Ni^(2+)ions into Fe^(3+)sites.The magnetic investigation reveals that Ni-doped FeVO_(4) exhibits weak ferromagnetic behavior at room temperature,in contrast to the antiferromagnetic behavior observed in the undoped FeVO_(4).Electrochemical studies demonstrate that the Fe_(0.95)Ni_(0.05)VO_(4) electrode achieves the highest specific capacitance of 334.05 F·g^(−1) at a current density of 1 A·g^(−1),which is attributed to its smallest average pore diameter.In addition,the enhanced specific surface of the Fe_(0.8)Ni_(0.2)VO_(4) electrode is responsible for its outstanding cyclic stability.Overall,our results suggest that the magnetic and electrochemical properties of FeVO_(4) nanoparticles could be effectively tuned by varying Ni doping contents.展开更多
p-type transparent oxide semiconductors(TOSs)are significant in the semiconductor industry,driving advancements in optoelectronic technologies for transparent electronic devices with unique properties.The recent disco...p-type transparent oxide semiconductors(TOSs)are significant in the semiconductor industry,driving advancements in optoelectronic technologies for transparent electronic devices with unique properties.The recent discovery of p-type behavior in SeO_(2) has stimulated interest and confusion in the scientific community.In this Letter,we employ density functional theory calculations to reveal the intrinsic intrinsic insulating characteristics of SeO_(2) and highlight the substantial challenges in carrier doping.Our electronic structure analyses indicate that the Se 5^(2) states are energetically positioned too low to effectively interact with the O 2p orbitals,resulting in a valence band maximum(VBM)primarily dominated by the O 2p orbitals.The deep and localized nature of the VBM of SeO_(2) limits its potential as a high-mobility p-type TOS.Defect calculations demonstrate that all intrinsic defects in SeO_(2) exhibit deep transition levels within the bandgap.Regardless of the synthesis conditions,the Fermi level consistently resides in the mid-gap region.Furthermore,deep intrinsic acceptors and donors exhibit negative formation energies in the n-type and p-type regions,respectively,facilitating spontaneous formation and impeding external doping efforts.Thus,the reported p-type conductivity in SeO_(2) samples is unlikely to be intrinsic and is more plausibly attributable to reduced elemental Se,a well-known p-type semiconductor.展开更多
By manipulating the distribution of surface electrons,defect engineering enables effective control over the adsorption energy between adsorbates and active sites in the CO_(2)reduction reaction(CO_(2)RR).Herein,we rep...By manipulating the distribution of surface electrons,defect engineering enables effective control over the adsorption energy between adsorbates and active sites in the CO_(2)reduction reaction(CO_(2)RR).Herein,we report a hollow indium oxide nanotube containing both oxygen vacancy and sulfur doping(V_o-Sx-In_(2)O_(3))for improved CO_(2)-to-HCOOH electroreduction and Zn-CO_(2)battery.The componential synergy significantly reduces the*OCHO formation barrier to expedite protonation process and creates a favorable electronic micro-environment for*HCOOH desorption.As a result,the CO_(2)RR performance of Vo-Sx-In_(2)O_(3)outperforms Pure-In_(2)O_(3)and V_o-In_(2)O_(3),where V_o-S53-In_(2)O_(3)exhibits a maximal HCOOH Faradaic efficiency of 92.4%at-1,2 V vs.reversible hydrogen electrode(RHE)in H-cell and above 92%over a wide window potential with high current density(119.1 mA cm^(-2)at-1.1 V vs.RHE)in flow cell.Furthermore,the rechargeable Zn-CO_(2)battery utilizing V_o-S53-In_(2)O_(3)as cathode shows a high power density of 2.29 mW cm^(-2)and a long-term stability during charge-discharge cycles.This work provides a valuable perspective to elucidate co-defective catalysts in regulating the intermediates for efficient CO_(2)RR.展开更多
Single-crystalline Ni-rich cathodes can provide high energy density and capacity retention rates for lithium-ion batteries(LIBs).However,single-crystalline Ni-rich cathodes experience severe transition metal dissoluti...Single-crystalline Ni-rich cathodes can provide high energy density and capacity retention rates for lithium-ion batteries(LIBs).However,single-crystalline Ni-rich cathodes experience severe transition metal dissolution,irreversible phase transitions,and reduced structural stability during prolonged cycling at high voltage,which will significantly hinder their practical application.Herein,a Li4TeO5surface coating along with bulk Te-gradient doping strategy is proposed and developed to solve these issues for single-crystalline Ni-rich LiNi_(0.90)Co_(0.05)Mn_(0.05)O_(2)cathode(LTeO-1.0).It has been found that the bulk Te^(6+)gradient doping can lead to the formation of robust Te-O bonds that effectively inhibit H_(2)-H3 phase transformations and reinforce the lattice framework,and the in-situ Li4TeO5coating layer can act as a protective layer that suppresses the parasitic reactions and grain fragmentation.Besides,the modified material exhibits a higher Young's modulus,which will be conducive to maintaining significant structural and electrochemical stability under high-voltage conditions,Especially,the LTeO-1.0 electrode shows the improved Li^(+)diffusion kinetics and thermodynamic stability as well as high capacity retention of 95.83%and 82.12%after 200 cycles at the cut-off voltage of 4.3 and 4,5 V.Therefore,the efficacious dualmodification strategy will definitely contribute to enhancing the structural and electrochemical stability of single-crystalline Ni-rich cathodes and developing their application in LIBs.展开更多
Blood doping remains a significant problem that threatensthe integrity ofsport.The currentindirect method for detecting blood doping involves the longitudinal measurement of an athlete’s haematological variables and i...Blood doping remains a significant problem that threatensthe integrity ofsport.The currentindirect method for detecting blood doping involves the longitudinal measurement of an athlete’s haematological variables and identification of suspicious results that are indicative of doping(i.e.,the athlete biological passport).While this has played a significant role in the protection of clean sport,improvements are needed.The development of a transcriptomic test,that can be used to detect the use of blood doping has been discussed and researched for decades and yet,an anti-doping test that can be adopted by the World Anti-Doping Agency(WADA)is yet to be established.With recent advancements in our understanding,as well as in methods of sample collection,the possibility of a transcriptomic test that can be used by WADA,is imminent.There are,however,several practical considerations that mustfirst be made,that will be highlighted in this perspective article.展开更多
Graphitic carbon nitride(g-C_(3)N_(4))has been extensively doped with alkali metals to enlarge photocatalytic output,in which cesium(Cs)doping is predicted to be the most efficient.Nevertheless,the sluggish diffusion ...Graphitic carbon nitride(g-C_(3)N_(4))has been extensively doped with alkali metals to enlarge photocatalytic output,in which cesium(Cs)doping is predicted to be the most efficient.Nevertheless,the sluggish diffusion and doping kinetics of precursors with high melting points,along with imprecise regulation,have raised the debate on whether Cs doping could make sense.For this matter,we attempt to confirm the positive effects of Cs doping on multifunctional photocatalysis by first using cesium acetate with the character of easy manipulation.The optimized Csdoped g-C_(3)N_(4)(CCN)shows a 41.6-fold increase in visible-light-driven hydrogen evolution reaction(HER)compared to pure g-C_(3)N_(4) and impressive degradation capability,especially with 77%refractory tetracycline and almost 100%rhodamine B degradedwithin an hour.The penetration ofCs+is demonstrated to be a mode of interlayer doping,and Cs–N bonds(especially with sp^(2) pyridine N in C═N–C),along with robust chemical interaction and electron exchange,are fabricated.This atomic configuration triggers the broadened spectral response,the improved charge migration,and the activated photocatalytic capacity.Furthermore,we evaluate the CCN/cadmium sulfide hybrid as a Z-scheme configuration,promoting the visible HER yield to 9.02 mmol g^(−1) h^(−1),which is the highest ever reported among all CCN systems.This work adds to the rapidly expanding field of manipulation strategies and supports further development of mediating served for photocatalysis.展开更多
Electrocatalytic hydrogen production from seawater holds enormous promise for clean energy generation.Nevertheless,the direct electrolysis of seawater encounters significant challenges due to poor anodic stability cau...Electrocatalytic hydrogen production from seawater holds enormous promise for clean energy generation.Nevertheless,the direct electrolysis of seawater encounters significant challenges due to poor anodic stability caused by detrimental chlorine chemistry.Herein,we present our recent discovery that the incorporation of Ce into Ni Fe layered double hydroxide nanosheet array on Ni foam(Ce-Ni Fe LDH/NF)emerges as a robust electrocatalyst for seawater oxidation.During the seawater oxidation process,CeO_(2)is generated,effectively repelling Cl^(-)and inhibiting the formation of Cl O-,resulting in a notable enhancement in the oxidation activity and stability of alkaline seawater.The prepared Ce-Ni Fe LDH/NF requires only overpotential of 390 m V to achieve the current density of 1 A cm^(-2),while maintaining long-term stability for 500 h,outperforming the performance of Ni Fe LDH/NF(430 m V,150 h)by a significant margin.This study highlights the effectiveness of a Ce-doping strategy in augmenting the activity and stability of materials based on Ni Fe LDH in seawater electrolysis for oxygen evolution.展开更多
The self-made MnFeO_(x) catalysts doped with cerium and samarium were prepared by impregnation method for low-temperature selective catalytic reduction(SCR)by NH3.In this work,the surface properties of the series of M...The self-made MnFeO_(x) catalysts doped with cerium and samarium were prepared by impregnation method for low-temperature selective catalytic reduction(SCR)by NH3.In this work,the surface properties of the series of MnFe-based catalysts were studied.The results indicate Sm-modified catalyst have superior low-temperature SCR activity;NO_(x) conversion maintained at nearby to 100%at 90℃ to 240℃.In addition,The N_(2) selectivity of Sm doping remains above 80%in the range of 60℃ to 150℃.In SO_(2) poisoning test,the NO_(x) conversion can be remained>90%after 10 h of reaction.The XPS,NH_(3)-TPD and H_(2)-TPR results show the catalyst with Sm doping enhances the acid sites and oxidation catalytic sites of mixed oxides serves for improving oxygen vacancies and transfer electrons.In situ diffuse reflaxions infrared Fourier transformations spectroscopy(DRIFTS)results show that NO_(x) is more easily adsorbed on the surface after Sm doping,which provided favorable conditions for the NH_(3)-SCR reaction to proceed.The reaction at the catalyst surface will follow the L-H reaction mechanism by transient reaction test.展开更多
Graphene's large theoretical surface area and high conductivity make it an attractive anode material for potassium-ion batteries(PIBs).However,its practical application is hindered by small interlayer distance and...Graphene's large theoretical surface area and high conductivity make it an attractive anode material for potassium-ion batteries(PIBs).However,its practical application is hindered by small interlayer distance and long ion transfer distance.Herein,this paper aims to address the issue by introducing MXene through a simple and scalable method for assembling graphene and realizing ultrahigh P doping content.The findings reveal that MXene and P-C bonds have a "pillar effect" on the structure of graphene,and the P-C bond plays a primary role.In addition,N/P co-doping introduces abundant defects,providing more active sites for K^(+) storage and facilitating K^(+) adsorption.As expected,the developed ultrahigh phosphorous/nitrogen co-doped flexible reduced graphene oxide/MXene(NPrGM) electrode exhibits remarkable reversible discharge capacity(554 mA hg^(-1) at 0.05 A g^(-1)),impressive rate capability(178 mA h g^(-1) at 2 A g^(-1)),and robust cyclic stability(0.0005% decay per cycle after 10,000 cycles at 2 A g^(-1)).Furthermore,the assembled activated carbon‖NPrGM potassium-ion hybrid capacitor(PIHC) can deliver an impressive energy density of 131 W h kg^(-1) and stable cycling performance with 98.1% capacitance retention after5000 cycles at 1 A g^(-1).Such a new strategy will effectively promote the practical application of graphene materials in PIBs/PIHCs and open new avenues for the scalable development of flexible films based on two-dimensional materials for potential applications in energy storage,thermal interface,and electromagnetic shielding.展开更多
Rechargeable magnesium batteries(RMBs)hold promise for offering higher volumetric energy density and safety features,attracting increasing research interest as the next post lithium-ion batteries.Developing high perfo...Rechargeable magnesium batteries(RMBs)hold promise for offering higher volumetric energy density and safety features,attracting increasing research interest as the next post lithium-ion batteries.Developing high performance cathode material by inducing multi-electron reaction process as well as maintaining structural stability is the key to the development and application of RMBs.Herein,multielectron reaction occurred in VS_(4)by simple W doping strategy.W doping induces valence of partial V as V^(2+)and V^(3+)in VS_(4)structure,and then stimulates electrochemical reaction involving multi-electrons in 0.5%W-V-S.The flower-like microsphere morphology as well as rich S vacancies is also modulated by W doping to neutralize structure change in such multi-electron reaction process.The fabricated 0.5%W-V-S delivers higher specific capacity(149.3 m A h g^(-1)at 50 m A g^(-1),which is 1.6 times higher than that of VS_(4)),superior rate capability(76 mA h g^(-1)at 1000 mA g^(-1)),and stable cycling performance(1500cycles with capacity retention ratio of 93.8%).Besides that,pesudocapaticance-like contribution analysis as well as galvanostatic intermittent titration technique(GITT)further confirms the enhanced Mg^(2+)storage kinetics during such multi-electron involved electrochemical reaction process.Such discovery provides new insights into the designing of multi-electron reaction process in cathode as well as neutralizing structural change during such reaction for realizing superior electrochemical performance in energy storage devices.展开更多
Sodium with low cost and high abundance is considered as a substitute element of lithium for batteries and supercapacitors,which need the appropriate host materials to accommodate the relatively large Na^(+) ions.Comp...Sodium with low cost and high abundance is considered as a substitute element of lithium for batteries and supercapacitors,which need the appropriate host materials to accommodate the relatively large Na^(+) ions.Compared to Li^(+) storage,Na^(+) storage makes higher demands on the structural optimization of perovskite bismuth ferrite(BiFeO_(3)).We propose a novel strategy of defect engineering on BiFeO_(3) through Na and V codoping for high-efficiency Na^(+) storage,to reveal the roles of oxygen vacancies and V ions played in the enhanced electrochemical energy storage performances of Na-ion capacitors.The formation of the oxygen vacancies in the Na and V codoped BiFeO_(3)(denoted as NV-BFO),is promoted by Na doping and suppressed by V doping,which can be demonstrated by XPS and EPR spectra.By the first-principles calculations,the oxygen vacancies and V ions in NV-BFO are confirmed to substantially lower the Na^(+)migration energy barriers through the space and electric field effects,to effectively promote the Na^(+) transport in the crystals.Electrochemical kinetic analysis of the NV-BFO//NV-BFO capacitors indicates the dominant capacitive-controlled capacity,which depends on fast Na^(+) deintercalation-intercalation process in the NV-BFO electrode.The NV-BFO//NV-BFO capacitors open up a new avenue for developing highperformance Na-ion capacitors.展开更多
基金support from Queensland University of Technology,Brisbane,Queensland,Australiafinancial support from ARC Discovery Project(DP210103266).
文摘In this work,we have applied molybdenum(Mo)and titanium(Ti)co-doping to solve the degradation of Ni-rich cathodes.The modified cathode,i.e.,Li(Ni_(0.89)Co_(0.05)Mn_(0.05)Mo_(0.005)Ti_(0.005))O_(2) holds a stable structure with expanded crystal lattice distance which improves Li ion diffusion kinetics.The dopants have suppressed the growth of primary particles,formed a coating on the surface,and promoted the elongated morphology.Moreover,the mechanical strength of these particles has increased,as confirmed by the nanoindentation test,which can help suppress particle cracking.The detrimental H2-H3 phase transition has been postponed by 90 mV allowing the cathode to operate at a higher voltage.A better cycling stability over 100 cycles with 69%capacity retention has been observed.We believe this work points out a way to improve the cycling performance,Coulombic efficiency and capacity retention in Ni-rich cathodes.
基金supported by the National Natural Science Foundation of China(Grant Nos.52372150,12088101,and 11991060)the National Key R&D Program of China(Grant No.2022YFB4200305)。
文摘Wide-bandgap two-dimensional (2D) β-TeO_(2) has been reported as a high-mobility p-type transparent semiconductor [Nat. Electron. 4 277 (2021)], attracting significant attention. This "breakthrough" not only challenges the conventional characterization of TeO_(2) as an insulator but also conflicts with the anticipated difficulty in hole doping of TeO_(2) by established chemical trends. Notably, the reported Fermi level of 0.9 eV above the valence band maximum actually suggests that the material is an insulator, contradicting the high hole density obtained by Hall effect measurement. Furthermore, the detected residual Se and the possible reduced elemental Te in the 2D β-TeO_(2) samples introduces complexity, considering that elemental Se, Te, and Te_(1−x)Se_(x) themselves are high-mobility p-type semiconductors. Therefore, doubts regarding the true cause of the p-type conductivity observed in the 2D β-TeO_(2) samples arise. In this Letter, we employ density functional theory calculations to illustrate that TeO_(2), whether in its bulk forms of α-, β-, or γ-TeO_(2), or in the 2D β-TeO_(2) nanosheets, inherently exhibits insulating properties and poses challenges in carrier doping due to its shallow conduction band minimum and deep valence band maximum. Our findings shed light on the insulating properties and doping difficulty of TeO_(2), contrasting with the claimed p-type conductivity in the 2D β-TeO_(2) samples, prompting inquiries into the true origin of the p-type conductivity.
基金supported by the National Natural Science Foundation of China(62204074)the Hebei Natural Science Foundation(F2022201061,F2023201025)+2 种基金the Open bidding for selecting the best candidates of Baoding(2023chuang206)the High-level Talent Research Startup Project of Hebei University(521100221085)the Post-graduate's Innovation Fund Project of Hebei University(HBU2024BS030).
文摘Despite sulfurization offers the advantage of improving the photovoltaic performance in preparing Cu(In,Ga)Se2(CIGS)absorbers,deep level defects in the absorber and poor energy level alignment on the front surface are still main obstacles limiting the improvement of power co nversion efficiency(PCE)in sulfided CIGS solar cells.Herein,an in-situ Na doping strategy is proposed,in which the tailing effect of crystal growth is used to promote the sulfurization of CIGS absorbers.It is found that the grain growth is supported by Na incorporating due to the enrichment of NaSe_(x)near the upper surface.The high soluble Na during grain growth can not only suppress intrinsic In_(Cu) donor defects in the absorber,but also tailor S distribution in bulk and the band alignment at the heterojunction,which are both beneficial for the effective electron carriers.Meanwhile,the Na aggregation near the bottom of the absorber also contributes to the crystalline quality increasing and favorable ultra-thin MoSe_(2) formation at back contact,resulting in a reduced barrier height conducive to hole transport.PCE of the champion device is as high as 16.76%with a 28%increase.This research offers new insights into synthesizing CIGS solar cells and other chalcogenide solar cells with superior cell performance when using an intense sulfurization process.
基金National Natural Science Foundation of China (62104061, 62074052, 61974173 and 52072327)。
文摘Solution-processed Cu(In,Ga)Se_(2)(CIGS) solar cells suffer from serious carrier recombination and power conversion efficiency(PCE) loss because of the poor film properties and easy formation of defects.Herein, we propose Ag&Se co-selenization strategy to enhance the crystallization and passivate harmful defects of the CIGS films. The formation of Ag-Se phase during the selenization process enables the formation of large grains and suppresses the deep level defects. It is found that Ag doping can enlarge the depletion region width, lower the Urbach energy and prolong the carrier lifetime. As a result, a champion solution-processed CIGS solar cell presents a high efficiency of 16.48% with the highly improved opencircuit voltage(VOC) of 662 m V and fill factor(FF) of 75.8%. This work provides an efficient strategy to prepare high quality solution-processed CIGS films for high-performance CIGS solar cells.
文摘Ti at the oxidation states of Ti^(3+)and Ti^(4+),was used to enhance the performance of Na_(3)V_(2)(PO_(4))_(2)F_(2)O by partially substituting vanadium.After doping Ti,the crystallographic volume is decreased due to the less radii of Ti^(3+/4+),and the valence of Ti is demonstrated identical to V.During sodium insertion in Ti-doped Na_(3)V_(2)(PO_(4))_(2)F_(2)O,the two discharge plateaus split into three because of the rearrangement of local redox environment.Consequently,the optimized Na_(3)V_(0.96)Ti_(0.04)(PO_(4))_(2)F_(2)O shows a specific capacity of 123 and 63 mA·h/g at 0.1C and 20C,respectively.After 350 cycles at 0.5C,the capacity is gradually reduced corresponding to a retention of 71.05%.The significantly improved performance is attributed to the rapid electrochemical kinetics,and showcases the strategy of replacing V^(3+/4+)with Ti^(3+/4+)for high-performance vanadium-based oxyfluorophosphates.
基金National Natural Science Foundation of China (Nos. 42276035, 22309030)Guangdong Basic and Applied Basic Research Foundation (Nos. 2023A1515012589,2020A1515110473)Key Plat Form Programs and Technology Innovation Team Project of Guangdong Provincial Department of Education (Nos. 2019GCZX002, 2020KCXTD011)。
文摘Seawater electrolysis is a promising approach for sustainable energy without relying on precious freshwater.However,the large-scale seawater electrolysis is hindered by low catalytic efficiency and severe anode corrosion caused by the harmful chlorine.In contrast to the oxygen evolution reaction (OER)and chlorin ion oxidation reaction (ClOR),glycerol oxidation reaction (GOR) is more thermodynamically and kinetically favorable alternative.Herein,a Ru doping cobalt phosphide (Ru-CoP_(2)) is proposed as a robust bifunctional electrocatalyst for seawater electrolysis and GOR,for the concurrent productions of hydrogen and value-added formate.The in situ and ex situ characterization analyses demonstrated that Ru doping featured in the dynamic reconstruction process from Ru-CoP_(2)to Ru-CoOOH,accounting for the superior GOR performance.Further coupling GOR with hydrogen evolution was realized by employing Ru-CoP_(2)as both anode and cathode,requiring only a low voltage of 1.43 V at 100 mA cm^(-2),which was 250 m V lower than that in alkaline seawater.This work guides the design of bifunctional electrocatalysts for energy-efficient seawater electrolysis coupled with biomass resource upcycling.
基金National Key Research and Development Program of China (2022YFE0206300)National Natural Science Foundation of China (U21A2081,22075074, 22209047)+3 种基金Guangdong Basic and Applied Basic Research Foundation (2024A1515011620)Hunan Provincial Natural Science Foundation of China (2024JJ5068)Foundation of Yuelushan Center for Industrial Innovation (2023YCII0119)Student Innovation Training Program (S202410532594,S202410532357)。
文摘Hard carbon (HC) has been considered as promising anode material for sodium-ion batteries (SIBs).The optimization of hard carbon’s microstructure and solid electrolyte interface (SEI) property are demonstrated effective in enhancing the Na+storage capability,however,a one-step regulation strategy to achieve simultaneous multi-scale structures optimization is highly desirable.Herein,we have systematically investigated the effects of boron doping on hard carbon’s microstructure and interface chemistry.A variety of structure characterizations show that appropriate amount of boron doping can increase the size of closed pores via rearrangement of carbon layers with improved graphitization degree,which provides more Na+storage sites.In-situ Fourier transform infrared spectroscopy/electrochemical impedance spectroscopy (FTIR/EIS) and X-ray photoelectron spectroscopy (XPS) analysis demonstrate the presence of more BC3and less B–C–O structures that result in enhanced ion diffusion kinetics and the formation of inorganic rich and robust SEI,which leads to facilitated charge transfer and excellent rate performance.As a result,the hard carbon anode with optimized boron doping content exhibits enhanced rate and cycling performance.In general,this work unravels the critical role of boron doping in optimizing the pore structure,interface chemistry and diffusion kinetics of hard carbon,which enables rational design of sodium-ion battery anode with enhanced Na+storage performance.
基金support from the National Key Research and Development Program of China(No.2022YFE0137400)the National Natural Science Foundation of China(Grant No.62274040).
文摘The past decade has witnessed the rapid increasement in power conversion efficiency of perovskite solar cells(PSCs).However,serious ion migration hampers their operational stability.Although dopants composed of varied cations and anions are introduced into perovskite to suppress ion migration,the impact of cations or anions is not individually explored,which hinders the evaluation of different cations and further application of doping strategy.Here we report that a special group of sulfonic anions(like CF_(3)SO_(3)^(-))successfully introduce alkaline earth ions(like Ca^(2+))into perovskite lattice compared to its halide counterparts.Furthermore,with effective crystallization regulation and defect passivation of sulfonic anions,perovskite with Ca(CF_(3)SO_(3))_(2)shows reduced PbI2 residue and metallic Pb0 defects;thereby,corresponding PSCs show an enhanced PCE of 24.95%.Finally by comparing the properties of perovskite with Ca(CF_(3)SO_(3))_(2)and FACF_(3)SO_(3),we found that doped Ca^(2+)significantly suppressed halide migration with an activation energy of 1.246 eV which accounts for the improved operational stability of Ca(CF_(3)SO_(3))_(2-)doped PSCs,while no obvious impact of Ca^(2+)on trap density is observed.Combining the benefits of cations and anions,this study presents an effective method to decouple the effects of cations and anions and fabricate efficient and stable PSCs.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant No.U2030114the CASHIPS Director’s Fund(Grant No.YZJJ202207-CX)。
文摘Black-phosphorus-structured nitrogen(BP-N)is an attractive high-energy-density material.However,high-pressure-synthesized BP-N will decompose at low pressure and cannot be quenched to ambient conditions.Finding a method to stabilize it at 0 GPa is of great significance for its practical applications.However,unlike cubic gauche,layered polymeric,and hexagonal layered polymeric nitrogen(cg-N,LP-N,and HLP-N),it is always a metastable phase at high pressures up to 260 GPa,and decomposes into chains at 23 GPa.Here,on the basis of firstprinciples simulations,we find that P-atom doping can effectively reduce the synthesis pressure of BP-N and maintain its stability at 0 GPa.Uniform distribution of P-atom dopants within BP-N layers helps maintain the structural stability of these layers at 0 GPa,while interlayer electrostatic interaction induced by N-P dipoles enhances dynamic stability by eliminating interlayer slipping.Furthermore,pressure is conducive to enhancing the stability of BP-N and its doped forms by suppressing N-chain dissociation.For a configuration with 12.5%doping concentration,a gravimetric energy density of 8.07 kJ/g can be realized,which is nearly twice that of trinitrotoluene.
文摘The Fe_(1−x)Ni_(x)VO_(4)(x=0,0.05,0.10,and 0.20)nanoparticles in this work were successfully synthesized via a co-precipitation method.The structural,magnetic and electrochemical properties of the prepared Fe_(1−x)Ni_(x)VO_(4) nanoparticles were studied as a function of Ni content.The experimental results show that the prepared Ni-doped FeVO_(4) samples have a triclinic structure.Scanning electron microscopy(SEM)images reveal a decrease in average nanoparticle size with increasing Ni content,leading to an enhancement in both specific surface area and magnetization values.X-ray absorption near edge structure(XANES)analysis confirms the substitution of Ni^(2+)ions into Fe^(3+)sites.The magnetic investigation reveals that Ni-doped FeVO_(4) exhibits weak ferromagnetic behavior at room temperature,in contrast to the antiferromagnetic behavior observed in the undoped FeVO_(4).Electrochemical studies demonstrate that the Fe_(0.95)Ni_(0.05)VO_(4) electrode achieves the highest specific capacitance of 334.05 F·g^(−1) at a current density of 1 A·g^(−1),which is attributed to its smallest average pore diameter.In addition,the enhanced specific surface of the Fe_(0.8)Ni_(0.2)VO_(4) electrode is responsible for its outstanding cyclic stability.Overall,our results suggest that the magnetic and electrochemical properties of FeVO_(4) nanoparticles could be effectively tuned by varying Ni doping contents.
基金financially supported by the National Natural Science Foundation of China(Grant No.52372150)。
文摘p-type transparent oxide semiconductors(TOSs)are significant in the semiconductor industry,driving advancements in optoelectronic technologies for transparent electronic devices with unique properties.The recent discovery of p-type behavior in SeO_(2) has stimulated interest and confusion in the scientific community.In this Letter,we employ density functional theory calculations to reveal the intrinsic intrinsic insulating characteristics of SeO_(2) and highlight the substantial challenges in carrier doping.Our electronic structure analyses indicate that the Se 5^(2) states are energetically positioned too low to effectively interact with the O 2p orbitals,resulting in a valence band maximum(VBM)primarily dominated by the O 2p orbitals.The deep and localized nature of the VBM of SeO_(2) limits its potential as a high-mobility p-type TOS.Defect calculations demonstrate that all intrinsic defects in SeO_(2) exhibit deep transition levels within the bandgap.Regardless of the synthesis conditions,the Fermi level consistently resides in the mid-gap region.Furthermore,deep intrinsic acceptors and donors exhibit negative formation energies in the n-type and p-type regions,respectively,facilitating spontaneous formation and impeding external doping efforts.Thus,the reported p-type conductivity in SeO_(2) samples is unlikely to be intrinsic and is more plausibly attributable to reduced elemental Se,a well-known p-type semiconductor.
基金supported by the Fundamental Research Funds for the Central Universities(22120230104).
文摘By manipulating the distribution of surface electrons,defect engineering enables effective control over the adsorption energy between adsorbates and active sites in the CO_(2)reduction reaction(CO_(2)RR).Herein,we report a hollow indium oxide nanotube containing both oxygen vacancy and sulfur doping(V_o-Sx-In_(2)O_(3))for improved CO_(2)-to-HCOOH electroreduction and Zn-CO_(2)battery.The componential synergy significantly reduces the*OCHO formation barrier to expedite protonation process and creates a favorable electronic micro-environment for*HCOOH desorption.As a result,the CO_(2)RR performance of Vo-Sx-In_(2)O_(3)outperforms Pure-In_(2)O_(3)and V_o-In_(2)O_(3),where V_o-S53-In_(2)O_(3)exhibits a maximal HCOOH Faradaic efficiency of 92.4%at-1,2 V vs.reversible hydrogen electrode(RHE)in H-cell and above 92%over a wide window potential with high current density(119.1 mA cm^(-2)at-1.1 V vs.RHE)in flow cell.Furthermore,the rechargeable Zn-CO_(2)battery utilizing V_o-S53-In_(2)O_(3)as cathode shows a high power density of 2.29 mW cm^(-2)and a long-term stability during charge-discharge cycles.This work provides a valuable perspective to elucidate co-defective catalysts in regulating the intermediates for efficient CO_(2)RR.
基金supported by the National Natural Science Foundation of China(U19A2018)the Natural Science Foundation of Hunan Province(2021JJ30651)the Postgraduate Scientific Research Innovation Project of Hunan Province(CX20230643).
文摘Single-crystalline Ni-rich cathodes can provide high energy density and capacity retention rates for lithium-ion batteries(LIBs).However,single-crystalline Ni-rich cathodes experience severe transition metal dissolution,irreversible phase transitions,and reduced structural stability during prolonged cycling at high voltage,which will significantly hinder their practical application.Herein,a Li4TeO5surface coating along with bulk Te-gradient doping strategy is proposed and developed to solve these issues for single-crystalline Ni-rich LiNi_(0.90)Co_(0.05)Mn_(0.05)O_(2)cathode(LTeO-1.0).It has been found that the bulk Te^(6+)gradient doping can lead to the formation of robust Te-O bonds that effectively inhibit H_(2)-H3 phase transformations and reinforce the lattice framework,and the in-situ Li4TeO5coating layer can act as a protective layer that suppresses the parasitic reactions and grain fragmentation.Besides,the modified material exhibits a higher Young's modulus,which will be conducive to maintaining significant structural and electrochemical stability under high-voltage conditions,Especially,the LTeO-1.0 electrode shows the improved Li^(+)diffusion kinetics and thermodynamic stability as well as high capacity retention of 95.83%and 82.12%after 200 cycles at the cut-off voltage of 4.3 and 4,5 V.Therefore,the efficacious dualmodification strategy will definitely contribute to enhancing the structural and electrochemical stability of single-crystalline Ni-rich cathodes and developing their application in LIBs.
文摘Blood doping remains a significant problem that threatensthe integrity ofsport.The currentindirect method for detecting blood doping involves the longitudinal measurement of an athlete’s haematological variables and identification of suspicious results that are indicative of doping(i.e.,the athlete biological passport).While this has played a significant role in the protection of clean sport,improvements are needed.The development of a transcriptomic test,that can be used to detect the use of blood doping has been discussed and researched for decades and yet,an anti-doping test that can be adopted by the World Anti-Doping Agency(WADA)is yet to be established.With recent advancements in our understanding,as well as in methods of sample collection,the possibility of a transcriptomic test that can be used by WADA,is imminent.There are,however,several practical considerations that mustfirst be made,that will be highlighted in this perspective article.
基金supported primarily by the National Natural Science Foundation of China(Contract No.21975245,51972300,62274155,and U20A20206)the National Key Research and Development Program of China(Grant No.2018YFE0204000)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB43000000)the National Natural Science Foundation of China under Grant No.62175231.Prof.Kong Liu appreciates the support from the Youth Innovation Promotion Association,the Chinese Academy of Sciences(No.2020114)the Beijing Nova Program(No.2020117).
文摘Graphitic carbon nitride(g-C_(3)N_(4))has been extensively doped with alkali metals to enlarge photocatalytic output,in which cesium(Cs)doping is predicted to be the most efficient.Nevertheless,the sluggish diffusion and doping kinetics of precursors with high melting points,along with imprecise regulation,have raised the debate on whether Cs doping could make sense.For this matter,we attempt to confirm the positive effects of Cs doping on multifunctional photocatalysis by first using cesium acetate with the character of easy manipulation.The optimized Csdoped g-C_(3)N_(4)(CCN)shows a 41.6-fold increase in visible-light-driven hydrogen evolution reaction(HER)compared to pure g-C_(3)N_(4) and impressive degradation capability,especially with 77%refractory tetracycline and almost 100%rhodamine B degradedwithin an hour.The penetration ofCs+is demonstrated to be a mode of interlayer doping,and Cs–N bonds(especially with sp^(2) pyridine N in C═N–C),along with robust chemical interaction and electron exchange,are fabricated.This atomic configuration triggers the broadened spectral response,the improved charge migration,and the activated photocatalytic capacity.Furthermore,we evaluate the CCN/cadmium sulfide hybrid as a Z-scheme configuration,promoting the visible HER yield to 9.02 mmol g^(−1) h^(−1),which is the highest ever reported among all CCN systems.This work adds to the rapidly expanding field of manipulation strategies and supports further development of mediating served for photocatalysis.
基金support from the Free Exploration Project of Frontier Technology for Laoshan Laboratory(No.16-02)the National Natural Science Foundation of China(Nos.22072015 and 21927811)。
文摘Electrocatalytic hydrogen production from seawater holds enormous promise for clean energy generation.Nevertheless,the direct electrolysis of seawater encounters significant challenges due to poor anodic stability caused by detrimental chlorine chemistry.Herein,we present our recent discovery that the incorporation of Ce into Ni Fe layered double hydroxide nanosheet array on Ni foam(Ce-Ni Fe LDH/NF)emerges as a robust electrocatalyst for seawater oxidation.During the seawater oxidation process,CeO_(2)is generated,effectively repelling Cl^(-)and inhibiting the formation of Cl O-,resulting in a notable enhancement in the oxidation activity and stability of alkaline seawater.The prepared Ce-Ni Fe LDH/NF requires only overpotential of 390 m V to achieve the current density of 1 A cm^(-2),while maintaining long-term stability for 500 h,outperforming the performance of Ni Fe LDH/NF(430 m V,150 h)by a significant margin.This study highlights the effectiveness of a Ce-doping strategy in augmenting the activity and stability of materials based on Ni Fe LDH in seawater electrolysis for oxygen evolution.
基金supported by the Fundamental Research Funds for the Central Universities(222201817001)Shanghai Sailing Program(21YF140800).
文摘The self-made MnFeO_(x) catalysts doped with cerium and samarium were prepared by impregnation method for low-temperature selective catalytic reduction(SCR)by NH3.In this work,the surface properties of the series of MnFe-based catalysts were studied.The results indicate Sm-modified catalyst have superior low-temperature SCR activity;NO_(x) conversion maintained at nearby to 100%at 90℃ to 240℃.In addition,The N_(2) selectivity of Sm doping remains above 80%in the range of 60℃ to 150℃.In SO_(2) poisoning test,the NO_(x) conversion can be remained>90%after 10 h of reaction.The XPS,NH_(3)-TPD and H_(2)-TPR results show the catalyst with Sm doping enhances the acid sites and oxidation catalytic sites of mixed oxides serves for improving oxygen vacancies and transfer electrons.In situ diffuse reflaxions infrared Fourier transformations spectroscopy(DRIFTS)results show that NO_(x) is more easily adsorbed on the surface after Sm doping,which provided favorable conditions for the NH_(3)-SCR reaction to proceed.The reaction at the catalyst surface will follow the L-H reaction mechanism by transient reaction test.
基金financially supported by the National Natural Science Foundation of China (52172192)the Young Top-Notch Talent of National Ten Thousand Talent Program (W03070054)。
文摘Graphene's large theoretical surface area and high conductivity make it an attractive anode material for potassium-ion batteries(PIBs).However,its practical application is hindered by small interlayer distance and long ion transfer distance.Herein,this paper aims to address the issue by introducing MXene through a simple and scalable method for assembling graphene and realizing ultrahigh P doping content.The findings reveal that MXene and P-C bonds have a "pillar effect" on the structure of graphene,and the P-C bond plays a primary role.In addition,N/P co-doping introduces abundant defects,providing more active sites for K^(+) storage and facilitating K^(+) adsorption.As expected,the developed ultrahigh phosphorous/nitrogen co-doped flexible reduced graphene oxide/MXene(NPrGM) electrode exhibits remarkable reversible discharge capacity(554 mA hg^(-1) at 0.05 A g^(-1)),impressive rate capability(178 mA h g^(-1) at 2 A g^(-1)),and robust cyclic stability(0.0005% decay per cycle after 10,000 cycles at 2 A g^(-1)).Furthermore,the assembled activated carbon‖NPrGM potassium-ion hybrid capacitor(PIHC) can deliver an impressive energy density of 131 W h kg^(-1) and stable cycling performance with 98.1% capacitance retention after5000 cycles at 1 A g^(-1).Such a new strategy will effectively promote the practical application of graphene materials in PIBs/PIHCs and open new avenues for the scalable development of flexible films based on two-dimensional materials for potential applications in energy storage,thermal interface,and electromagnetic shielding.
基金supported by the National Natural Science Foundation of China under Grant No.52072196,52002200,52102106,52202262,22379081,and 22379080Major Basic Research Program of the Natural Science Foundation of Shandong Province under Grant No.ZR2020ZD09+1 种基金the Natural Science Foundation of Shandong Province under Grant No.ZR2020QE063,ZR202108180009,ZR2023QE059the Postdoctoral Program in Qingdao under No.QDBSH20220202019。
文摘Rechargeable magnesium batteries(RMBs)hold promise for offering higher volumetric energy density and safety features,attracting increasing research interest as the next post lithium-ion batteries.Developing high performance cathode material by inducing multi-electron reaction process as well as maintaining structural stability is the key to the development and application of RMBs.Herein,multielectron reaction occurred in VS_(4)by simple W doping strategy.W doping induces valence of partial V as V^(2+)and V^(3+)in VS_(4)structure,and then stimulates electrochemical reaction involving multi-electrons in 0.5%W-V-S.The flower-like microsphere morphology as well as rich S vacancies is also modulated by W doping to neutralize structure change in such multi-electron reaction process.The fabricated 0.5%W-V-S delivers higher specific capacity(149.3 m A h g^(-1)at 50 m A g^(-1),which is 1.6 times higher than that of VS_(4)),superior rate capability(76 mA h g^(-1)at 1000 mA g^(-1)),and stable cycling performance(1500cycles with capacity retention ratio of 93.8%).Besides that,pesudocapaticance-like contribution analysis as well as galvanostatic intermittent titration technique(GITT)further confirms the enhanced Mg^(2+)storage kinetics during such multi-electron involved electrochemical reaction process.Such discovery provides new insights into the designing of multi-electron reaction process in cathode as well as neutralizing structural change during such reaction for realizing superior electrochemical performance in energy storage devices.
基金financial supports from National Natural Science Foundation of China(22005174 and 52271133)。
文摘Sodium with low cost and high abundance is considered as a substitute element of lithium for batteries and supercapacitors,which need the appropriate host materials to accommodate the relatively large Na^(+) ions.Compared to Li^(+) storage,Na^(+) storage makes higher demands on the structural optimization of perovskite bismuth ferrite(BiFeO_(3)).We propose a novel strategy of defect engineering on BiFeO_(3) through Na and V codoping for high-efficiency Na^(+) storage,to reveal the roles of oxygen vacancies and V ions played in the enhanced electrochemical energy storage performances of Na-ion capacitors.The formation of the oxygen vacancies in the Na and V codoped BiFeO_(3)(denoted as NV-BFO),is promoted by Na doping and suppressed by V doping,which can be demonstrated by XPS and EPR spectra.By the first-principles calculations,the oxygen vacancies and V ions in NV-BFO are confirmed to substantially lower the Na^(+)migration energy barriers through the space and electric field effects,to effectively promote the Na^(+) transport in the crystals.Electrochemical kinetic analysis of the NV-BFO//NV-BFO capacitors indicates the dominant capacitive-controlled capacity,which depends on fast Na^(+) deintercalation-intercalation process in the NV-BFO electrode.The NV-BFO//NV-BFO capacitors open up a new avenue for developing highperformance Na-ion capacitors.
