Three star-shaped truxene-based small molecules（namely TXH,TXM,TXO） were synthesized,characterized and used as hole-transporting materials（HTMs） for perovskite solar cells（Pv SCs）. The device based on TXO delive...Three star-shaped truxene-based small molecules（namely TXH,TXM,TXO） were synthesized,characterized and used as hole-transporting materials（HTMs） for perovskite solar cells（Pv SCs）. The device based on TXO delivered a respectable power conversion efficiency（PCE） of 7.89% and a high open-circuit voltage（Voc） of 0.97 V,which far exceeded the values of the devices based on other two small molecules. The highest PCE for the device based on TXO is mainly contributed from its lowest series resistance（Rs） value and largest short-circuit current（Jsc） value under the same circumstances. All these results indicate that TXO is a promising HTM candidate for Pv SCs.展开更多
It is challenging for aqueous Zn-ion batteries(ZIBs)to achieve comparable low-temperature(low-T)performance due to the easy-frozen electrolyte and severe Zn dendrites.Herein,an aqueous electrolyte with a low freezing ...It is challenging for aqueous Zn-ion batteries(ZIBs)to achieve comparable low-temperature(low-T)performance due to the easy-frozen electrolyte and severe Zn dendrites.Herein,an aqueous electrolyte with a low freezing point and high ionic conductivity is proposed.Combined with molecular dynamics simulation and multi-scale interface analysis(time of flight secondary ion mass spectrometry threedimensional mapping and in-situ electrochemical impedance spectroscopy method),the temperature independence of the V_(2)O_(5)cathode and Zn anode is observed to be opposite.Surprisingly,dominated by the solvent structure of the designed electrolyte at low temperatures,vanadium dissolution/shuttle is significantly inhibited,and the zinc dendrites caused by this electrochemical crosstalk are greatly relieved,thus showing an abnormal temperature inversion effect.Through the disclosure and improvement of the above phenomena,the designed Zn||V_(2)O_(5)full cell delivers superior low-T performance,maintaining almost 99%capacity retention after 9500 cycles(working more than 2500 h)at-20°C.This work proposes a kind of electrolyte suitable for low-T ZIBs and reveals the inverse temperature dependence of the Zn anode,which might offer a novel perspective for the investigation of low-T aqueous battery systems.展开更多
A flexible electrode of nickel diselenide/carbon fiber cloth(NiSe/CFC) is fabricated at room temperature by a simple and efficient electrodeposition method. Owing to NiSecharacter of nanostructure and high conductivit...A flexible electrode of nickel diselenide/carbon fiber cloth(NiSe/CFC) is fabricated at room temperature by a simple and efficient electrodeposition method. Owing to NiSecharacter of nanostructure and high conductivity, the as-synthesized electrodes possess perfect pseudocapacitive property with high specific capacitance and excellent rate capability. In three-electrode system, the electrode specific capacitance of the NiSe/CFC electrode varies from 1058 F gto 996.3 F gat 2 A gto 10 A grespectively, which shows great rate capability. Moreover, the NiSeelectrode is assembled with an active carbon(AC) electrode to form an asymmetric supercapacitor with an extended potential window of 1.6 V. The asymmetric supercapacitor possesses an excellent energy density 32.7 Wh kgwith a power density 800 W kgat the current density of 1 A g. The nanosheet array on carbon fiber cloth with high flexibility, specific capacitance and rate capacitance render the NiSeto be regarded as the promising material for the high performance superconductor.展开更多
Sodium-ion batteries(SIB) have attracted widespread attention in large-scale energy storage fields owing to the abundant reserve in the earth and similar properties of sodium to lithium. Biomass-based carbon materials...Sodium-ion batteries(SIB) have attracted widespread attention in large-scale energy storage fields owing to the abundant reserve in the earth and similar properties of sodium to lithium. Biomass-based carbon materials with low-cost, controllable structure, simple processing technology, and environmental friendliness tick almost all the right boxes as one of the promising anode materials for SIB. Herein, we present a simple novel strategy involving tea tomenta biomass-derived carbon anode with enhanced interlayer carbon distance(0.44 nm) and high performance, which is constructed by N,P co-doped hard carbon(Tea-1100-NP) derived from tea tomenta. The prepared Tea-1100-NP composite could deliver a high reversible capacity(326.1 m Ah/g at 28 m A/g), high initial coulombic efficiency(ICE = 90% at 28 m A/g),stable cycle life(262.4 m Ah/g at 280 m A/g for 100 cycles), and superior rate performance(224.5 m Ah/g at 1400 m A/g). Experimental results show that the excellent electrochemical performance of Tea-1100-NP due to the high number of active N,P-containing groups, and disordered amorphous structures provide ample active sites and increase the conductivity, meanwhile, large amounts of microporous shorten the Na+diffusion distance as well as quicken ion transport. This work provides a new type of N,P co-doped high-performance tomenta-derived carbon, which may also greatly promote the commercial application of SIB.展开更多
Perovskite solar cells have developed rapidly in the past decades.However,there are large amounts of ionic defects at the surface and grain boundaries of perovskte films which are detrimental to both the efficiency an...Perovskite solar cells have developed rapidly in the past decades.However,there are large amounts of ionic defects at the surface and grain boundaries of perovskte films which are detrimental to both the efficiency and stability of perovskite solar cells.Here,an organic halide salt pyridinium iodide(PyI) is used in cation-anion-mixed perovskite for surface defect passivation.Different from the treatment with Lewis base pyridine(Py) which can only bind to the under-coordinated Pb ions,zwitterion molecule PyI can not only fill negative charged iodine vacancies,but also interact with positive charged defects.Compared with Py treatment,PyI treatment results in smoother surface,less defect densities and nonradiative recombination in perovskite,leading to an improved VOC, negligible J-V hysteresis and stable performance of devices.As a result,the champion PyI-treated planar perovskite solar cell with a high VOC of 1.187 V achieves an efficiency of 21.42%,which is higher than 20.37% of Py-treated device,while the pristine device without any treatment gets an efficiency of 18.83% at the same experiment conditions.展开更多
Co-free Li-rich layered oxide cathodes have drawn much attention owing to their low cost and high energy density.Nevertheless,anion oxidation of oxygen leads to oxygen peroxidation during the first charging process,wh...Co-free Li-rich layered oxide cathodes have drawn much attention owing to their low cost and high energy density.Nevertheless,anion oxidation of oxygen leads to oxygen peroxidation during the first charging process,which leads to co-migration of transition metal ions and oxygen vacancies,causing structural instability.In this work,we propose a pre-activation strategy driven by chemical impregnation to modulate the chemical state of surface lattice oxygen,thus regulating the structural and electrochemical properties of the cathodes.In-situ X-ray diffraction confirms that materials based on activated oxygen configuration have higher structural stability.More importantly,this novel efficient strategy endows the cathodes having a lower surface charge transfer barrier and higher Li+transfer kinetics characteristic and ameliorates its inherent issues.The optimized cathode exhibits excellent electrochemical performance:after 300 cycles,high capacity(from 238 m Ah g^(-1)to 193 m Ah g^(-1)at 1 C)and low voltage attenuation(168 mV)are obtained.Overall,this modulated surface lattice oxygen strategy improves the electrochemical activity and structural stability,providing an innovative idea to obtain high-capacity Co-free Li-rich cathodes for next-generation Li-ion batteries.展开更多
Lithium-sulfur(Li-S)batteries with high theoretical capacity and energy density need to solve problems such as the high decomposition energy barrier of Li_(2)S and large volume change of sulfur in the charging process...Lithium-sulfur(Li-S)batteries with high theoretical capacity and energy density need to solve problems such as the high decomposition energy barrier of Li_(2)S and large volume change of sulfur in the charging process caused by the shuttle effect before practical application.Herein,a green synthesis method is used to prepare polyacrylic acid(PAA)superabsorbent material,and then the pyrolyzed PAA(P/PAA)material is obtained as the positive electrode of Li-S battery.Density functional calculation reveals that the oxygen self-doping pyrolyzed polyacrylic acid(P/PAA)delivered stronger binding energy toward Li2S species in carbonyl C=O than that of graphite powder(GP)which are-1.58 eV and-1.02 eV,respectively.Coupled with the distribution of relaxation time analysis and the in-situ electrochemical impedance approach,it is further demonstrated that the designed P/PAA as sulfur host plays a physical/chemical adsorption dual function in maintaining the stability and rate performance of batteries.With an initial discharge capacity of 1258 mAh/g at 0.1 C and a minimal capacity decline of 0.05%per cycle even after 800 cycles at 0.5 C,the produced cathode demonstrated outstanding electrochemical performance.The average Coulombic efficiency is nearly 100%.The P/PAA electrodes may typically retain 96%of their capacity while declining on average only 0.033%per cycle after 130 cycles at 3 C.This effort provides a new method for the future development of heteroatomic self-doping superabsorbent with promising adsorption properties for polysulfides as cathode materials of Li-S batteries.展开更多
Achieving an in-depth understanding of the nexus between temperature and phase transitions is paramount for advancing the electrochemical efficiency of aqueous zinc ion batteries.Yet,the intricacies of electrochemical...Achieving an in-depth understanding of the nexus between temperature and phase transitions is paramount for advancing the electrochemical efficiency of aqueous zinc ion batteries.Yet,the intricacies of electrochemical interactions,particularly those associated with the structural evolution over extended periods,remain enigmatic.In this research,we leverage V_(2)O_(5) as an initial structural model of crystals to demystify the kinetics of electrode reactions and the decay mechanism of global electrochemical degradation by meticulously controlling the crystal defects via applying different mechanical grounding intensities.It is noted that the grounding V_(2)O_(5)(GVO)can exhibit a stable crystal structure that suppresses the dissolution/shuttling of vanadium and mitigates Zn anodes by-products caused by electrochemical processes.Thus,the GVO is utilized as the cathode material,achieving excellent Zn storage capacity at both room temperature and low temperatures,e.g.,380 and 246 mA h g^(−1) at room temperature and−20℃,respectively.Remarkably,the GVO cathode retains a specific capacity of 160 mA h g^(−1) with a capacity retention rate of 99%after 1500 cycles at−20℃ and 1 A g^(−1).This work provides a novel insight into the electrochemical crosstalk behavior of aqueous zinc-ion batteries(AZIBs)in a wide range of temperatures.展开更多
Gd_2O_3 :Eu^(3+) downconversion luminescent powder was prepared using the homogeneous precipitation method. Its optical properties were analyzed and it was introduced into a dye-sensitized solar cell (DSSC). As a lumi...Gd_2O_3 :Eu^(3+) downconversion luminescent powder was prepared using the homogeneous precipitation method. Its optical properties were analyzed and it was introduced into a dye-sensitized solar cell (DSSC). As a luminescence medium, Gd_2O_3 :Eu^(3+) improved light harvesting via conversion luminescence and increased the photocurrent of the DSSC. As a p-type dopant insulating rare earth oxides form an energy barrier, and the Gd_2O_3 :Eu^(3+) elevated the energy level of the oxide film and increased the photovoltage. The photoelectric conversion efficiency for a DSSC with Gd_2O_3 :Eu^(3+) doping (6 : 100) reached 7.01%, which was 17.4% higher than the photoelectrical conversion efficiency of a DSSC without Gd 2 O 3 :Eu 3+ doping.展开更多
Achieving simultaneous fast-charging capabilities and low-temperature adaptability in graphite-based lithium-ion batteries(LIBs)with an acceptable cycle life remains challenging.Herein,an ether-based electrolyte with ...Achieving simultaneous fast-charging capabilities and low-temperature adaptability in graphite-based lithium-ion batteries(LIBs)with an acceptable cycle life remains challenging.Herein,an ether-based electrolyte with temperature-adaptive Li^(+)solvation structure is designed for graphite,and stable Li^(+)/solvent co-intercalation has been achieved at subzero.As revealed by in-situ variable temperature(-20℃)X-ray diffraction(XRD),the poor compatibility of graphite in ether-based electrolyte at 25℃is mainly due to the continuous electrolyte decomposition and the in-plane rearrangement below0.5 V.Former results in a significant irreversible capacity,while latter maintains graphite in a prolonged state of extreme expansion,ultimately leading to its exfoliation and failure.In contrast,low temperature triggers the rearra ngement of Li^(+)solvation structu re with stronger Li^(+)/solvent binding energy and sho rter Li^(+)-O bond length,which is conducive for reversible Li^(+)/solvent co-intercalation and reducing the time of graphite in an extreme expansion state.In addition,the co-intercalation of solvents minimizes the interaction between Li-ions and host graphite,endowing graphite with fast diffusion kinetics.As expected,the graphite anode delivers about 84%of the capacity at room temperature at-20℃.Moreover,within6 min,about 83%,73%,and 43%of the capacity could be charged at 25,-20,and-40℃,respectively.展开更多
Covalent organic framework(COF)materials have gained significant applications in electrocatalytic systems due to their structural diversity and tunable functionalities.Moreover,three-dimensional(3D)COFs exhibit multis...Covalent organic framework(COF)materials have gained significant applications in electrocatalytic systems due to their structural diversity and tunable functionalities.Moreover,three-dimensional(3D)COFs exhibit multistage pore structures,exposing numerous open sites,which facilitate the oxygen reduction reaction(ORR)process.However,the advancement of 3D COFs for ORR has been hindered by challenges,including limited topologies,the scarcity of building blocks with the required reactivity and symmetries,and difficulties in determining crystalline structures.In this work,we utilized an 8-connectivity building unit and successfully constructed two isoreticular 3D COF materials,which exhibited exceptionally high catalytic activity for 2e−oxygen reduction reaction without the addition of any metal or conductive support materials,nor the pyrolyzed process.The electrochemically active surface areas(ECSAs)of the two 3D COFs were found to be 17.19 and 12.18 mF/cm2,respectively,which were significantly higher than those reported from other framework materials.展开更多
An upconversion luminescence powder TiO2:(Er3+,Yb3+) is prepared by a hydrothermal method and used to fabricate dye-sensitized solar cell (DSSC).The TiO2:(Er3+,Yb3+) powder undergoes upconversion luminescence,converti...An upconversion luminescence powder TiO2:(Er3+,Yb3+) is prepared by a hydrothermal method and used to fabricate dye-sensitized solar cell (DSSC).The TiO2:(Er3+,Yb3+) powder undergoes upconversion luminescence,converting infrared light which the dye can not absorb into visible light with wavelengths of 510-700 nm which the dye can absorb,increasing the photocurrent of the DSSC.TiO2:(Er3+,Yb3+) also acts as a p-type dopant,heightening the Fermi level of the oxide film,which increases the photovoltage of the DSSC.The best performance of the DSSC is found when the ratio of TiO2/luminescence powder is 1/3 in the luminescence layer.Under simulated solar irradiation of 100 mW cm-2 (AM 1.5),the DSSC containing TiO2:(Er3+,Yb3+) doping achieves a light-to-electricity energy conversion efficiency of 7.28% compared with 6.41% for the undoped DSSC.展开更多
A simple method for the controllable hydrothermal synthesis of nanocrystalline anatase TiO2(nc-TiO2) particles involving the selection of suitable organic alkali peptizing agents is reported.A dye-sensitized solar cel...A simple method for the controllable hydrothermal synthesis of nanocrystalline anatase TiO2(nc-TiO2) particles involving the selection of suitable organic alkali peptizing agents is reported.A dye-sensitized solar cell(DSSC) with square-like nc-TiO2 particles with side lengths about 8-13 nm-prepared using tetraethylammonium hydroxide(TEAOH)-in the photoelectrode showed higher photovoltaic performance than two other DSSCs with square-like nc-TiO2 particles with side lengths about 7-10 nm-prepared using tetrabutylammonium hydroxide-or elongated nc-TiO2 particles with lengths about 18-35 nm and width about 10 18 nm-prepared using tetramethylammonium hydroxide(TMAOH)-in the photoelectrodes.When a scattering layer prepared from sub-micron size spheres or cone-like nc-TiO2 particles-synthesized using a higher concentration of TMAOH-was added on top of the photoelectrode fabricated from nc-TiO2 synthesized with TEAOH,the energy conversion efficiency of the DSSC was markedly increased from 6.77% to 8.18%.展开更多
Using blend heterojunction consisting of C60 derivatives [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and poly(3-hexylthiophene) (P3HT) as charge carrier transferring medium to replace I3–/I– redox electrolyte,...Using blend heterojunction consisting of C60 derivatives [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and poly(3-hexylthiophene) (P3HT) as charge carrier transferring medium to replace I3–/I– redox electrolyte,a novel flexible dye-sensitized solar cell (DSSC) is fabricated.The characterization of infrared spectra and ultraviolet-visible spectra shows that the PCBM/P3HT heterojunction has not only the absorption in ultraviolet light for PCBM,but also the absorption in visible and near infrared light for P3HT,which widens the photoelectric response range for DSSC.The influence of PCBM/P3HT mass ratio on the performance of the solar cell is discussed.Under 100 mW cm–2 (AM 1.5) simulated solar irradiation,the flexible solar cell achieves a lightto-electric energy conversion efficiency of 1.43%,open circuit voltage of 0.87 V,short circuit current density of 3.0 mA cm–2 and fill factor of 0.54.展开更多
Tin-based perovskite solar cells(TPSCs)as the most promising candidate for lead-free PSCs have incurred extensive researches all over the world.However,the crystallization process of tin-based perovskite is too fast d...Tin-based perovskite solar cells(TPSCs)as the most promising candidate for lead-free PSCs have incurred extensive researches all over the world.However,the crystallization process of tin-based perovskite is too fast during the solution-deposited process,resulting in abundant pinholes and poor homogeneity that cause serious charge recombination in perovskite layer.Here,we employed theπ-conjugated Lewis base molecules with high electron density to systematically control the crystallization rate of FASnI3 perovskite by forming stable intermediate phase with the Sn-I frameworks,leading to a compact and uniform perovskite film with large increase in the carrier lifetime.Meanwhile,the introduction of theπ-conjugated systems also retards the permeation of moisture into perovskite crystal,which significantly suppresses the film degradation in air.These benefits contributed to a stabilizing power conversion efficiency(PCE)of 10.1%for the TPSCs and maintained over 90%of its initial PCE after 1000-h light soaking in air.Also,a steady-state efficiency of 9.2%was certified at the accredited test center.展开更多
A TiO2 paste was prepared by mixing commercial TiO2 (P25), ethanol, distilled water and a small amount of Ti (IV) tetrai-sopropoxide (TTIP), following by a hydrothermal treatment. Before hydrothermal treatment, a stir...A TiO2 paste was prepared by mixing commercial TiO2 (P25), ethanol, distilled water and a small amount of Ti (IV) tetrai-sopropoxide (TTIP), following by a hydrothermal treatment. Before hydrothermal treatment, a stirring for 48 h can prevent cracking TiO2 films. TTIP significantly promote the chemical connection between TiO2 particles and its adherence to the substrate, the TTIP amount of 6 mol% is suitable. UV irradiation can remove some impurities and water from the TiO2 film with an optimal time of 2 h. Transmission electron microscopy, X-ray diffraction, scanning electron microscopy and photovoltaic tests are charac- terized and measured. Shortcircuit current density, open-circuit voltage, fill factor and photoelectric conversion efficiencies for the fabricated flexible dye-sensitized solar cell are 7.20 mA cm-2, 0.769 V, 0.686 and 3.84%, respectively, under irradiation with a simulated solar light of 100 mW cm-2.展开更多
Mesoporous TiO2microsphere(MTM)was synthesized via a simple solution route and then mixed with commercial TiO2(P25)to form highly homogeneous and stable TiO2colloid by simple hydrothermal treatment.The TiO2colloid was...Mesoporous TiO2microsphere(MTM)was synthesized via a simple solution route and then mixed with commercial TiO2(P25)to form highly homogeneous and stable TiO2colloid by simple hydrothermal treatment.The TiO2colloid was coated onto the plastic conductive substrate to prepare mesoporous TiO2film for flexible dye-sensitized solar cells(DSSCs)by low-temperature heat treatment.The influence of MTM content on the physicochemical properties of the flexible TiO2film was characterized by scanning electron microscope,transmission electron microscopy,X-ray diffraction,energy-dispersive X-ray spectrometer,N2adsorption-desorption isotherms,UV–vis absorption and diffuse reflectance spectra.It is revealed that with increasing the MTM content,the dye-loading capability of TiO2film and light-harvesting efficiency of flexible DSSCs are improved due to MTM having high surface area and acting as a light scattering center,respectively,resulting in the enhancement of photocurrent of flexible DSSCs.However,more and larger cracks having negative effect on the performances of flexible DSSCs are formed simultaneously.Under the optimal condition with MTM content of 20%,a flexible DSSC with overall light-to-electric energy conversion efficiency of 2.74%is achieved under a simulated solar light irradiation of 100 mW cm 2(AM 1.5),with 26%improvement in comparison with DSSCs based on P25 alone.展开更多
This paper reports a novel strategy for preparing redox-active electrolyte through introducing a redox-mediator(p-phenylenediamine,PPD) into KOH electrolyte for the application of ball-milled MnO 2-based supercapacito...This paper reports a novel strategy for preparing redox-active electrolyte through introducing a redox-mediator(p-phenylenediamine,PPD) into KOH electrolyte for the application of ball-milled MnO 2-based supercapacitors.The morphology and compositions of ball-milled MnO 2 were characterized using scanning electron microscopy(SEM) and X-ray diffraction(XRD).The electrochemical properties of the supercapacitor were evaluated by cyclic voltammetry(CV),galvanostatic charge-discharge(GCD),and electrochemical impedance spectroscopy(EIS) techniques.The introduction of p-phenylenediamine significantly improves the performance of the supercapacitor.The electrode specific capacitance of the supercapacitor is 325.24 F g-1,increased by 6.25 folds compared with that of the unmodified system(44.87 F g-1) at the same current density,and the energy density has nearly a 10-fold increase,reaching 10.12 Wh Kg-1.In addition,the supercapacitor exhibits good cycle-life stability.展开更多
Novel, three-dimensional, flower-like Bi203/BiVO4 heterojunction photocatalysts have been prepared by the combination of homogeneous precipitation and two-step solvothermal method followed by thermal solu- tion of NaO...Novel, three-dimensional, flower-like Bi203/BiVO4 heterojunction photocatalysts have been prepared by the combination of homogeneous precipitation and two-step solvothermal method followed by thermal solu- tion of NaOH etching process. The as-obtained samples were fully characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, Brunauer-Emmett-Teller surface area, and UV-vis diffuse- reflectance spectroscopy in detail. The crystallinity, microstructure, specific surface area, optical property and photocatalytic activity of samples greatly changed depending on solvothermal reaction time. The photocatalytic activities of samples were evaluated on the degradation of methyl orange （MO） under visible-light irradiation. The Bi203/BiVO4 exhibited much higher photocatalytic activities than pure BiVO4 and conventional TiO2 （P25）. The result revealed that the three-dimensional heterojunction played a critical role in the separation of the electron and hole pairs and enhancement of the interfacial charge transfer efficiency, which was responsible for the enhanced photocatalytic activity.展开更多
A new kind of gel electrolyte containing only organic solvents and an iodide salt-namely 3-methoxypropionitrile(MPN),aniline and AlI 3 -has been prepared.Gel formation results from the Lewis acid-base interaction betw...A new kind of gel electrolyte containing only organic solvents and an iodide salt-namely 3-methoxypropionitrile(MPN),aniline and AlI 3 -has been prepared.Gel formation results from the Lewis acid-base interaction between the Lewis acid ionic conductor AlI 3 and the Lewis base organic solvent aniline and no additional gelling agent is required.The AlI 3-aniline complex acts both as an ionic conductor and as a gelling agent.The differences between the peaks characteristic of the-NH 2 group and aromatic ring in the FTIR spectra of free aniline and the AlI 3-aniline hybrid confirm the formation of the AlI 3-aniline complex.The photovoltaic performance and long-term stability of dye-sensitized solar cells can be greatly enhanced by the addition of aniline to the AlI 3-MPN liquid electrolyte.展开更多
基金supported by the National Natural Science Foundation of China(Nos.61325026,51503209)the Natural Science Foundation of Fujian Province(No.2015H0050)
文摘Three star-shaped truxene-based small molecules（namely TXH,TXM,TXO） were synthesized,characterized and used as hole-transporting materials（HTMs） for perovskite solar cells（Pv SCs）. The device based on TXO delivered a respectable power conversion efficiency（PCE） of 7.89% and a high open-circuit voltage（Voc） of 0.97 V,which far exceeded the values of the devices based on other two small molecules. The highest PCE for the device based on TXO is mainly contributed from its lowest series resistance（Rs） value and largest short-circuit current（Jsc） value under the same circumstances. All these results indicate that TXO is a promising HTM candidate for Pv SCs.
基金financially supported by the National Natural Science Foundation of China(52372191)the Natural Science Foundation of Xiamen,China(3502Z202372036)+1 种基金the China Postdoctoral Science Foundation(2022TQ0282)the support of the High-Performance Computing Center(HPCC)at Harbin Institute of Technology on first-principles calculations。
文摘It is challenging for aqueous Zn-ion batteries(ZIBs)to achieve comparable low-temperature(low-T)performance due to the easy-frozen electrolyte and severe Zn dendrites.Herein,an aqueous electrolyte with a low freezing point and high ionic conductivity is proposed.Combined with molecular dynamics simulation and multi-scale interface analysis(time of flight secondary ion mass spectrometry threedimensional mapping and in-situ electrochemical impedance spectroscopy method),the temperature independence of the V_(2)O_(5)cathode and Zn anode is observed to be opposite.Surprisingly,dominated by the solvent structure of the designed electrolyte at low temperatures,vanadium dissolution/shuttle is significantly inhibited,and the zinc dendrites caused by this electrochemical crosstalk are greatly relieved,thus showing an abnormal temperature inversion effect.Through the disclosure and improvement of the above phenomena,the designed Zn||V_(2)O_(5)full cell delivers superior low-T performance,maintaining almost 99%capacity retention after 9500 cycles(working more than 2500 h)at-20°C.This work proposes a kind of electrolyte suitable for low-T ZIBs and reveals the inverse temperature dependence of the Zn anode,which might offer a novel perspective for the investigation of low-T aqueous battery systems.
基金the financial joint support by the National Natural Science Foundation of China(nos.91422301,51472094,61474047)
文摘A flexible electrode of nickel diselenide/carbon fiber cloth(NiSe/CFC) is fabricated at room temperature by a simple and efficient electrodeposition method. Owing to NiSecharacter of nanostructure and high conductivity, the as-synthesized electrodes possess perfect pseudocapacitive property with high specific capacitance and excellent rate capability. In three-electrode system, the electrode specific capacitance of the NiSe/CFC electrode varies from 1058 F gto 996.3 F gat 2 A gto 10 A grespectively, which shows great rate capability. Moreover, the NiSeelectrode is assembled with an active carbon(AC) electrode to form an asymmetric supercapacitor with an extended potential window of 1.6 V. The asymmetric supercapacitor possesses an excellent energy density 32.7 Wh kgwith a power density 800 W kgat the current density of 1 A g. The nanosheet array on carbon fiber cloth with high flexibility, specific capacitance and rate capacitance render the NiSeto be regarded as the promising material for the high performance superconductor.
基金the support of this work by National Natural Science Foundation of China (Nos. 21771066, 21805278, 52072323,52122211)the “Double-First Class” Foundation of Materials and Intelligent Manufacturing Discipline of Xiamen University。
文摘Sodium-ion batteries(SIB) have attracted widespread attention in large-scale energy storage fields owing to the abundant reserve in the earth and similar properties of sodium to lithium. Biomass-based carbon materials with low-cost, controllable structure, simple processing technology, and environmental friendliness tick almost all the right boxes as one of the promising anode materials for SIB. Herein, we present a simple novel strategy involving tea tomenta biomass-derived carbon anode with enhanced interlayer carbon distance(0.44 nm) and high performance, which is constructed by N,P co-doped hard carbon(Tea-1100-NP) derived from tea tomenta. The prepared Tea-1100-NP composite could deliver a high reversible capacity(326.1 m Ah/g at 28 m A/g), high initial coulombic efficiency(ICE = 90% at 28 m A/g),stable cycle life(262.4 m Ah/g at 280 m A/g for 100 cycles), and superior rate performance(224.5 m Ah/g at 1400 m A/g). Experimental results show that the excellent electrochemical performance of Tea-1100-NP due to the high number of active N,P-containing groups, and disordered amorphous structures provide ample active sites and increase the conductivity, meanwhile, large amounts of microporous shorten the Na+diffusion distance as well as quicken ion transport. This work provides a new type of N,P co-doped high-performance tomenta-derived carbon, which may also greatly promote the commercial application of SIB.
基金the joint financial support from the National Natural Science Foundation of China (No. U1705256, 51972123, 21771066 and 61804058)the Cultivation Program for Postgraduate in Scientific Research Innovation Ability of Huaqiao University (No. 18014087027)。
文摘Perovskite solar cells have developed rapidly in the past decades.However,there are large amounts of ionic defects at the surface and grain boundaries of perovskte films which are detrimental to both the efficiency and stability of perovskite solar cells.Here,an organic halide salt pyridinium iodide(PyI) is used in cation-anion-mixed perovskite for surface defect passivation.Different from the treatment with Lewis base pyridine(Py) which can only bind to the under-coordinated Pb ions,zwitterion molecule PyI can not only fill negative charged iodine vacancies,but also interact with positive charged defects.Compared with Py treatment,PyI treatment results in smoother surface,less defect densities and nonradiative recombination in perovskite,leading to an improved VOC, negligible J-V hysteresis and stable performance of devices.As a result,the champion PyI-treated planar perovskite solar cell with a high VOC of 1.187 V achieves an efficiency of 21.42%,which is higher than 20.37% of Py-treated device,while the pristine device without any treatment gets an efficiency of 18.83% at the same experiment conditions.
基金the National Natural Science Foundation of China(51902072 and 22075062)the Heilongjiang Touyan Team(HITTY-20190033)+2 种基金the Heilongjiang Province“hundred million”project science and technology major special projects(2019ZX09A02)the State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology No.2020DX11)the Fundamental Research Funds for the Central Universities(FRFCU5710051922)。
文摘Co-free Li-rich layered oxide cathodes have drawn much attention owing to their low cost and high energy density.Nevertheless,anion oxidation of oxygen leads to oxygen peroxidation during the first charging process,which leads to co-migration of transition metal ions and oxygen vacancies,causing structural instability.In this work,we propose a pre-activation strategy driven by chemical impregnation to modulate the chemical state of surface lattice oxygen,thus regulating the structural and electrochemical properties of the cathodes.In-situ X-ray diffraction confirms that materials based on activated oxygen configuration have higher structural stability.More importantly,this novel efficient strategy endows the cathodes having a lower surface charge transfer barrier and higher Li+transfer kinetics characteristic and ameliorates its inherent issues.The optimized cathode exhibits excellent electrochemical performance:after 300 cycles,high capacity(from 238 m Ah g^(-1)to 193 m Ah g^(-1)at 1 C)and low voltage attenuation(168 mV)are obtained.Overall,this modulated surface lattice oxygen strategy improves the electrochemical activity and structural stability,providing an innovative idea to obtain high-capacity Co-free Li-rich cathodes for next-generation Li-ion batteries.
基金the financial support of the National Natural Science Foundation of China(Nos.22271106,21501175 and 2227518)the Natural Science Foundation of Fujian Province(No.2022Y0071)the Leading Project Foundation of Science Department of Fujian Province(No.2023H0045)。
文摘Lithium-sulfur(Li-S)batteries with high theoretical capacity and energy density need to solve problems such as the high decomposition energy barrier of Li_(2)S and large volume change of sulfur in the charging process caused by the shuttle effect before practical application.Herein,a green synthesis method is used to prepare polyacrylic acid(PAA)superabsorbent material,and then the pyrolyzed PAA(P/PAA)material is obtained as the positive electrode of Li-S battery.Density functional calculation reveals that the oxygen self-doping pyrolyzed polyacrylic acid(P/PAA)delivered stronger binding energy toward Li2S species in carbonyl C=O than that of graphite powder(GP)which are-1.58 eV and-1.02 eV,respectively.Coupled with the distribution of relaxation time analysis and the in-situ electrochemical impedance approach,it is further demonstrated that the designed P/PAA as sulfur host plays a physical/chemical adsorption dual function in maintaining the stability and rate performance of batteries.With an initial discharge capacity of 1258 mAh/g at 0.1 C and a minimal capacity decline of 0.05%per cycle even after 800 cycles at 0.5 C,the produced cathode demonstrated outstanding electrochemical performance.The average Coulombic efficiency is nearly 100%.The P/PAA electrodes may typically retain 96%of their capacity while declining on average only 0.033%per cycle after 130 cycles at 3 C.This effort provides a new method for the future development of heteroatomic self-doping superabsorbent with promising adsorption properties for polysulfides as cathode materials of Li-S batteries.
基金supported by the Natural Science Foundation of Xiamen, China (3502Z202372036)the National Natural Science Foundation of China (52372191, 52073286 (to CZ Lu), 22275185 (to CZ Lu))+4 种基金the Scientific Research Funds of Huaqiao University (20221XD027, 20221XD045)the Xiamen Institute of Rare Earth Materials Haixi Institutes (XMIREM)the Autonomously Deployment Project (2023GG01 (to CZ Lu))the Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China (2021ZZ115 (to CZ Lu))the China Postdoctoral Science Foundation (2022TQ0282)。
文摘Achieving an in-depth understanding of the nexus between temperature and phase transitions is paramount for advancing the electrochemical efficiency of aqueous zinc ion batteries.Yet,the intricacies of electrochemical interactions,particularly those associated with the structural evolution over extended periods,remain enigmatic.In this research,we leverage V_(2)O_(5) as an initial structural model of crystals to demystify the kinetics of electrode reactions and the decay mechanism of global electrochemical degradation by meticulously controlling the crystal defects via applying different mechanical grounding intensities.It is noted that the grounding V_(2)O_(5)(GVO)can exhibit a stable crystal structure that suppresses the dissolution/shuttling of vanadium and mitigates Zn anodes by-products caused by electrochemical processes.Thus,the GVO is utilized as the cathode material,achieving excellent Zn storage capacity at both room temperature and low temperatures,e.g.,380 and 246 mA h g^(−1) at room temperature and−20℃,respectively.Remarkably,the GVO cathode retains a specific capacity of 160 mA h g^(−1) with a capacity retention rate of 99%after 1500 cycles at−20℃ and 1 A g^(−1).This work provides a novel insight into the electrochemical crosstalk behavior of aqueous zinc-ion batteries(AZIBs)in a wide range of temperatures.
基金the National High Technology Research and Development Program of China (2009AA03Z217)the National Natural Science Foundation of China (90922028, 50842027)
文摘Gd_2O_3 :Eu^(3+) downconversion luminescent powder was prepared using the homogeneous precipitation method. Its optical properties were analyzed and it was introduced into a dye-sensitized solar cell (DSSC). As a luminescence medium, Gd_2O_3 :Eu^(3+) improved light harvesting via conversion luminescence and increased the photocurrent of the DSSC. As a p-type dopant insulating rare earth oxides form an energy barrier, and the Gd_2O_3 :Eu^(3+) elevated the energy level of the oxide film and increased the photovoltage. The photoelectric conversion efficiency for a DSSC with Gd_2O_3 :Eu^(3+) doping (6 : 100) reached 7.01%, which was 17.4% higher than the photoelectrical conversion efficiency of a DSSC without Gd 2 O 3 :Eu 3+ doping.
基金financially supported by the National Natural Science Foundation of China(52372191)the Natural Science Foundation of Fujian Province(2023J05047)+1 种基金the Natural Science Foundation of Xiamen,China(3502Z202372036)the support of the High-Performance Computing Center(HPCC)at Harbin Institute of Technology on first-principles calculations.
文摘Achieving simultaneous fast-charging capabilities and low-temperature adaptability in graphite-based lithium-ion batteries(LIBs)with an acceptable cycle life remains challenging.Herein,an ether-based electrolyte with temperature-adaptive Li^(+)solvation structure is designed for graphite,and stable Li^(+)/solvent co-intercalation has been achieved at subzero.As revealed by in-situ variable temperature(-20℃)X-ray diffraction(XRD),the poor compatibility of graphite in ether-based electrolyte at 25℃is mainly due to the continuous electrolyte decomposition and the in-plane rearrangement below0.5 V.Former results in a significant irreversible capacity,while latter maintains graphite in a prolonged state of extreme expansion,ultimately leading to its exfoliation and failure.In contrast,low temperature triggers the rearra ngement of Li^(+)solvation structu re with stronger Li^(+)/solvent binding energy and sho rter Li^(+)-O bond length,which is conducive for reversible Li^(+)/solvent co-intercalation and reducing the time of graphite in an extreme expansion state.In addition,the co-intercalation of solvents minimizes the interaction between Li-ions and host graphite,endowing graphite with fast diffusion kinetics.As expected,the graphite anode delivers about 84%of the capacity at room temperature at-20℃.Moreover,within6 min,about 83%,73%,and 43%of the capacity could be charged at 25,-20,and-40℃,respectively.
基金supported by the National Natural Science Foundation of China(22271106,22105202,22275185)China Postdoctoral Science Foundation(2021M693178,2022T150650)+3 种基金XIREM Autonomously Deployment Project(2023GG01)Fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China(2021ZZ115)Strategic Priority Research Program of the Chinese Academy of Sciences(XDB20000000)State Key Laboratory of Structural Chemistry,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences(20230027)。
文摘Covalent organic framework(COF)materials have gained significant applications in electrocatalytic systems due to their structural diversity and tunable functionalities.Moreover,three-dimensional(3D)COFs exhibit multistage pore structures,exposing numerous open sites,which facilitate the oxygen reduction reaction(ORR)process.However,the advancement of 3D COFs for ORR has been hindered by challenges,including limited topologies,the scarcity of building blocks with the required reactivity and symmetries,and difficulties in determining crystalline structures.In this work,we utilized an 8-connectivity building unit and successfully constructed two isoreticular 3D COF materials,which exhibited exceptionally high catalytic activity for 2e−oxygen reduction reaction without the addition of any metal or conductive support materials,nor the pyrolyzed process.The electrochemically active surface areas(ECSAs)of the two 3D COFs were found to be 17.19 and 12.18 mF/cm2,respectively,which were significantly higher than those reported from other framework materials.
基金supported by the National High Technology Research and Development Program of China (2009AA03Z217)the National Natural Science Foundation of China (90922028,50842027)
文摘An upconversion luminescence powder TiO2:(Er3+,Yb3+) is prepared by a hydrothermal method and used to fabricate dye-sensitized solar cell (DSSC).The TiO2:(Er3+,Yb3+) powder undergoes upconversion luminescence,converting infrared light which the dye can not absorb into visible light with wavelengths of 510-700 nm which the dye can absorb,increasing the photocurrent of the DSSC.TiO2:(Er3+,Yb3+) also acts as a p-type dopant,heightening the Fermi level of the oxide film,which increases the photovoltage of the DSSC.The best performance of the DSSC is found when the ratio of TiO2/luminescence powder is 1/3 in the luminescence layer.Under simulated solar irradiation of 100 mW cm-2 (AM 1.5),the DSSC containing TiO2:(Er3+,Yb3+) doping achieves a light-to-electricity energy conversion efficiency of 7.28% compared with 6.41% for the undoped DSSC.
基金supported by the National High Technology Research and Development of China (863 Program,2009AA03Z217)the National Natural Science Foundation of China (90922028,51002053)+1 种基金the Natural Science Foundation of Fujian Province (2010J05115)the Fundamental Research Funds for the Central Universities (JB-SJ1001)
文摘A simple method for the controllable hydrothermal synthesis of nanocrystalline anatase TiO2(nc-TiO2) particles involving the selection of suitable organic alkali peptizing agents is reported.A dye-sensitized solar cell(DSSC) with square-like nc-TiO2 particles with side lengths about 8-13 nm-prepared using tetraethylammonium hydroxide(TEAOH)-in the photoelectrode showed higher photovoltaic performance than two other DSSCs with square-like nc-TiO2 particles with side lengths about 7-10 nm-prepared using tetrabutylammonium hydroxide-or elongated nc-TiO2 particles with lengths about 18-35 nm and width about 10 18 nm-prepared using tetramethylammonium hydroxide(TMAOH)-in the photoelectrodes.When a scattering layer prepared from sub-micron size spheres or cone-like nc-TiO2 particles-synthesized using a higher concentration of TMAOH-was added on top of the photoelectrode fabricated from nc-TiO2 synthesized with TEAOH,the energy conversion efficiency of the DSSC was markedly increased from 6.77% to 8.18%.
基金supported by the National Natural Science Foundation of China (90922028)the National High-Tech Research and Development Program of China (2009AA03Z217)
文摘Using blend heterojunction consisting of C60 derivatives [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and poly(3-hexylthiophene) (P3HT) as charge carrier transferring medium to replace I3–/I– redox electrolyte,a novel flexible dye-sensitized solar cell (DSSC) is fabricated.The characterization of infrared spectra and ultraviolet-visible spectra shows that the PCBM/P3HT heterojunction has not only the absorption in ultraviolet light for PCBM,but also the absorption in visible and near infrared light for P3HT,which widens the photoelectric response range for DSSC.The influence of PCBM/P3HT mass ratio on the performance of the solar cell is discussed.Under 100 mW cm–2 (AM 1.5) simulated solar irradiation,the flexible solar cell achieves a lightto-electric energy conversion efficiency of 1.43%,open circuit voltage of 0.87 V,short circuit current density of 3.0 mA cm–2 and fill factor of 0.54.
基金supported by the National Natural Science Foundation of China(11574199,11674219,11834011)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning+1 种基金National Institute for Materials Science was supported by the New Energy and Industrial Technology Development Organization(NEDO,Japan)the KAKEHI Grant of Japan(18H02078)
文摘Tin-based perovskite solar cells(TPSCs)as the most promising candidate for lead-free PSCs have incurred extensive researches all over the world.However,the crystallization process of tin-based perovskite is too fast during the solution-deposited process,resulting in abundant pinholes and poor homogeneity that cause serious charge recombination in perovskite layer.Here,we employed theπ-conjugated Lewis base molecules with high electron density to systematically control the crystallization rate of FASnI3 perovskite by forming stable intermediate phase with the Sn-I frameworks,leading to a compact and uniform perovskite film with large increase in the carrier lifetime.Meanwhile,the introduction of theπ-conjugated systems also retards the permeation of moisture into perovskite crystal,which significantly suppresses the film degradation in air.These benefits contributed to a stabilizing power conversion efficiency(PCE)of 10.1%for the TPSCs and maintained over 90%of its initial PCE after 1000-h light soaking in air.Also,a steady-state efficiency of 9.2%was certified at the accredited test center.
基金supported by the National High Technology Research and Development Program of China (2009AA03Z217)the National Natu-ral Science Foundation of China (50842027, 90922028)
文摘A TiO2 paste was prepared by mixing commercial TiO2 (P25), ethanol, distilled water and a small amount of Ti (IV) tetrai-sopropoxide (TTIP), following by a hydrothermal treatment. Before hydrothermal treatment, a stirring for 48 h can prevent cracking TiO2 films. TTIP significantly promote the chemical connection between TiO2 particles and its adherence to the substrate, the TTIP amount of 6 mol% is suitable. UV irradiation can remove some impurities and water from the TiO2 film with an optimal time of 2 h. Transmission electron microscopy, X-ray diffraction, scanning electron microscopy and photovoltaic tests are charac- terized and measured. Shortcircuit current density, open-circuit voltage, fill factor and photoelectric conversion efficiencies for the fabricated flexible dye-sensitized solar cell are 7.20 mA cm-2, 0.769 V, 0.686 and 3.84%, respectively, under irradiation with a simulated solar light of 100 mW cm-2.
基金supported financially by the National High Technology Research and Development Program of China(2009AA03Z217)the National Natural Science Foundation of China(90922028)+1 种基金the Key Project of Chinese Ministry of Education(211204)the Fund of Fujian Provincial Key Laboratory of Nanomaterials(NM10-5)
文摘Mesoporous TiO2microsphere(MTM)was synthesized via a simple solution route and then mixed with commercial TiO2(P25)to form highly homogeneous and stable TiO2colloid by simple hydrothermal treatment.The TiO2colloid was coated onto the plastic conductive substrate to prepare mesoporous TiO2film for flexible dye-sensitized solar cells(DSSCs)by low-temperature heat treatment.The influence of MTM content on the physicochemical properties of the flexible TiO2film was characterized by scanning electron microscope,transmission electron microscopy,X-ray diffraction,energy-dispersive X-ray spectrometer,N2adsorption-desorption isotherms,UV–vis absorption and diffuse reflectance spectra.It is revealed that with increasing the MTM content,the dye-loading capability of TiO2film and light-harvesting efficiency of flexible DSSCs are improved due to MTM having high surface area and acting as a light scattering center,respectively,resulting in the enhancement of photocurrent of flexible DSSCs.However,more and larger cracks having negative effect on the performances of flexible DSSCs are formed simultaneously.Under the optimal condition with MTM content of 20%,a flexible DSSC with overall light-to-electric energy conversion efficiency of 2.74%is achieved under a simulated solar light irradiation of 100 mW cm 2(AM 1.5),with 26%improvement in comparison with DSSCs based on P25 alone.
基金supported by the National High Technology Research and Development Program of China (2009AA03Z217)the National Natural Science Foundation of China (90922028,50842027)the Key Project of Ministry of Education of China (211204)
文摘This paper reports a novel strategy for preparing redox-active electrolyte through introducing a redox-mediator(p-phenylenediamine,PPD) into KOH electrolyte for the application of ball-milled MnO 2-based supercapacitors.The morphology and compositions of ball-milled MnO 2 were characterized using scanning electron microscopy(SEM) and X-ray diffraction(XRD).The electrochemical properties of the supercapacitor were evaluated by cyclic voltammetry(CV),galvanostatic charge-discharge(GCD),and electrochemical impedance spectroscopy(EIS) techniques.The introduction of p-phenylenediamine significantly improves the performance of the supercapacitor.The electrode specific capacitance of the supercapacitor is 325.24 F g-1,increased by 6.25 folds compared with that of the unmodified system(44.87 F g-1) at the same current density,and the energy density has nearly a 10-fold increase,reaching 10.12 Wh Kg-1.In addition,the supercapacitor exhibits good cycle-life stability.
基金supported by the National Natural Science Foundation of China(Nos.61306077,21301060)the Fundamental Research Funds for the Central Universities(Nos.JB-ZR1109,JB-ZR1212)+3 种基金the National Science Foundation of Quanzhou City(No.2014Z108)the Promotion Program for Young and Middle-aged Teachers in Science and Technology Research of Huaqiao University(No.ZQN-PY207)Discipline Innovation Team Project of Huaqiao University(No.201320)the Instrumental Analysis Center Huaqiao University
文摘Novel, three-dimensional, flower-like Bi203/BiVO4 heterojunction photocatalysts have been prepared by the combination of homogeneous precipitation and two-step solvothermal method followed by thermal solu- tion of NaOH etching process. The as-obtained samples were fully characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, Brunauer-Emmett-Teller surface area, and UV-vis diffuse- reflectance spectroscopy in detail. The crystallinity, microstructure, specific surface area, optical property and photocatalytic activity of samples greatly changed depending on solvothermal reaction time. The photocatalytic activities of samples were evaluated on the degradation of methyl orange （MO） under visible-light irradiation. The Bi203/BiVO4 exhibited much higher photocatalytic activities than pure BiVO4 and conventional TiO2 （P25）. The result revealed that the three-dimensional heterojunction played a critical role in the separation of the electron and hole pairs and enhancement of the interfacial charge transfer efficiency, which was responsible for the enhanced photocatalytic activity.
基金supported by the National High Technology Research and Development of China (2009AA03Z217)the National Natural Science Foundation of China (51002053,90922028)+2 种基金the Natural Science Foundation of Fujian Province (E1050015)the Special Funds for Fundamental Operational Expenditures of Scientific Research of Huaqiao University(JB-SJ1001)the Key Lab of Novel Thin Film Solar Cells (KF200901),CAS
文摘A new kind of gel electrolyte containing only organic solvents and an iodide salt-namely 3-methoxypropionitrile(MPN),aniline and AlI 3 -has been prepared.Gel formation results from the Lewis acid-base interaction between the Lewis acid ionic conductor AlI 3 and the Lewis base organic solvent aniline and no additional gelling agent is required.The AlI 3-aniline complex acts both as an ionic conductor and as a gelling agent.The differences between the peaks characteristic of the-NH 2 group and aromatic ring in the FTIR spectra of free aniline and the AlI 3-aniline hybrid confirm the formation of the AlI 3-aniline complex.The photovoltaic performance and long-term stability of dye-sensitized solar cells can be greatly enhanced by the addition of aniline to the AlI 3-MPN liquid electrolyte.
