High-temperature proton exchange membrane fuel cells(HT-PEMFC) possess distinct technical advantages of high output power, simplified water/heat management, increased tolerance to fuel impurities and diverse fuel sour...High-temperature proton exchange membrane fuel cells(HT-PEMFC) possess distinct technical advantages of high output power, simplified water/heat management, increased tolerance to fuel impurities and diverse fuel sources, within the temperature range of 120–200 ℃. However, for practical automobile applications, it was crucial to broaden their low-temperature operating window and enable cold start-up capability. Herein, gel-state phosphoric acid(PA) doped sulfonated polybenzimidazole(PBI) proton exchange membranes(PEMs) were designed and synthesized via PPA sol-gel process and in-situ sultone ring-opening reactions with various proton transport pathways based on absorbed PA, flexible alkyl chain connected sulfonic acid groups and imidazole sites. The effects of flexible alkyl sulfonic acid side chain length and content on PA doping level, proton conductivity, and membrane stability under different temperature and relative humidity(RH) were thoroughly investigated. The prepared gel-state membranes contained a self-assembled lamellar and porous structure that facilitated the absorption of a large amount of PA with rapid proton transporting mechanisms. At room temperature, the optimized membrane exhibited a proton conductivity of 0.069 S cm^(-1), which was further increased to 0.162 and 0.358 S cm^(-1)at 80 and 200 ℃, respectively, without additional humidification. The most significant contribution of this work was demonstrating the feasibility of gel-state sulfonated PBI membranes in expanding HT-PEMFC application opportunities over a wider operating range of 25 to 240 ℃.展开更多
The electrolyte integrated with lithium metal anodes is subjected to the issues of interfacial compatibility and stability,which strongly influence the performances of high-energy lithium metal batteries.Here,we repor...The electrolyte integrated with lithium metal anodes is subjected to the issues of interfacial compatibility and stability,which strongly influence the performances of high-energy lithium metal batteries.Here,we report a new electrolyte recipe viz.a moderately concentrated electrolyte comprising of 2.4 M lithium bis(fluorosulfonyl)imide(LiFSI)in a cosolvent mixture of fluorinated ethylene carbonate(FEC)and dimethyl carbonate(DMC)with relatively high ion conductivity.Owing to the preferential decomposition of LiFSI and FEC,an inorganic-rich interphase with abundant Li_(2)O and LiF nanocrystals is formed on lithium metal with improved robustness and ion transfer kinetics,enabling lithium plating/stripping with an extremely low overpotential of~8 mV and the average CE of 97%.When tested in Li||LiFePO_(4) cell,this electrolyte provides long-term cycling with a capacity retention of 98.3%after 1000 cycles at 1 C and an excellent rate performance of 20 C,as well as an areal capacity of 1.35 mA h cm^(-2)at the cathode areal loading of 9 mg cm^(-2).Moreover,the Li||LiFePO_(4) cell exhibits excellent wide-temperature performances(-40~60℃),including long-term cycling stability over 2600 cycles without visible capacity fading at 0℃,as well as extremely high average CEs of 99.6%and 99.8% over 400 cycles under-20℃ and 45℃.展开更多
Currently,developing supercapacitors with robust cycle stability and suitability for wide-temperature-range operations is still a huge challenge.In the present work,few-layer hexagonal boron nitride nanosheets(h-BNNSs...Currently,developing supercapacitors with robust cycle stability and suitability for wide-temperature-range operations is still a huge challenge.In the present work,few-layer hexagonal boron nitride nanosheets(h-BNNSs)with a thickness of 2−4 atomic layers were fabricated via vacuum freeze-drying and nitridation.Then,the h-BNNSs/reduced graphene oxide(rGO)composite were further prepared using a hydrothermal method.Due to the combination of two two-dimensional(2D)van der Waals-bonded materials,the as-prepared h-BNNSs/rGO electrode exhibited robustness to wide-temperature-range operations from−10 to 50℃.When the electrodes worked in a neutral aqueous electrolyte(1 M Na2SO4),they showed a great stable cycling performance with almost 107%reservation of the initial capacitance at 0℃ and 111% at 50℃ for 5000 charge−discharge cycles.展开更多
Aqueous rechargeable batteries are safe and environmentally friendly and can be made at a low cost;as such,they are attracting attention in the field of energy storage.However,the temperature sensitivity of aqueous ba...Aqueous rechargeable batteries are safe and environmentally friendly and can be made at a low cost;as such,they are attracting attention in the field of energy storage.However,the temperature sensitivity of aqueous batteries hinders their practical application.The solvent water freezes at low temperatures,and there is a reduction in ionic conductivity,whereas it evaporates rapidly at high temperatures,which causes increased side reactions.This review discusses recent progress in improving the performance of aqueous batteries,mainly with respect to electrolyte engineering and the associated strategies employed to achieve such improvements over a wide temperature domain.The review focuses on fi ve electrolyte engineer-ing(aqueous high-concentration electrolytes,organic electrolytes,quasi-solid/solid electrolytes,hybrid electrolytes,and eutectic electrolytes)and investigates the mechanisms involved in reducing the solidifi cation point and boiling point of the electrolyte and enhancing the extreme-temperature electrochemical performance.Finally,the prospect of further improving the wide temperature range performance of aqueous rechargeable batteries is presented.展开更多
To achieve good performance for LiFePO4-based batteries operated at a wide temperature range,mixed salts of LiBF4 LiBOB（lithium bis（oxalato）borate） and LiTFSI（lithium bis（trifluoromethanesulfonyl）imide）-LiBOB ...To achieve good performance for LiFePO4-based batteries operated at a wide temperature range,mixed salts of LiBF4 LiBOB（lithium bis（oxalato）borate） and LiTFSI（lithium bis（trifluoromethanesulfonyl）imide）-LiBOB were investigated as alternative lithium salts to LiPF6 in non-aqueous electrolytes.LiFePO4/Li half cells using LiPF6,LiBF4-LiBOB and LiTFSI-LiBOB slats as lithium salts were investigated by galvanostatic cycling,cyclic voltammetry,thermogravimetric analysis.The results show that LiBF4-LiBOB and LiTFSI-LiBOB mixed salts are much more thermally stable than LiPF6.Corrosion of Al foil in the LiTFSI-based electrolytes can be suppressed successfully by the addition of LiBOB as a co-salt.The electrochemical performance of LiBF4-LiBOB and LiTFSI-LiBOB mixed salts based cells are both better than that of LiPF6-based cell.LiTFSI-LiBOB mixed salt based electrolyte is considered to be a very promising electrolyte candidate for Li-ion batteries that will be used in wide-temperature applications.展开更多
Transparent photovoltaic devices(TPVDs)have attracted increasing attention in emerging electronic devices.As the application scenarios extend,there raise higher requirements regarding the stability and operating tempe...Transparent photovoltaic devices(TPVDs)have attracted increasing attention in emerging electronic devices.As the application scenarios extend,there raise higher requirements regarding the stability and operating temperature range of TPVDs.In this work,a unique preparation strategy is proposed for air stable TPVD with a wide operating temperature range,i.e.,a nanoscale architecture termed as H-TPVD is constructed that integrates a free-standing and highly transparent conductive hybrid film of graphene and single-walled carbon nanotubes(G-SWNT TCF for short)with a metal oxide NiO/TiO_(2)heterojunction.The preparation approach is suitable for scaling up.Thanks to the excellent transparent conductivity of the freestanding G-SWNT hybrid film and the ultrathin NiO/TiO_(2)heterojunction(100 nm),H-TPVD selectively absorbs the ultraviolet(UV)band of sunlight and has a transparency of up to 71%in the visible light.The integrated nanoscale architecture manifests the significant holecollecting capability of the G-SWNT hybrid film and the efficient carrier generation and separation within the ultrathin NiO/TiO_(2)heterojunction,resulting in excellent performance of the H-TPVD with a specific detectivity of 2.7×10^(10) Jones.Especially,the freestanding G-SWNT TCF is a super stable and non-porous two-dimensional film that can insulate gas molecules,thereby protecting the surface properties of NiO/TiO_(2)heterojunctions and enhancing the stability of H-TPVD.Having subjected to 20,000 cycles and storage in air for three months,the performance parameters such as photo-response signal,output power,and specific detectivity show no noticeable degradation.In particular,the as-fabricated self-powered H-TPVD can operate over a wide temperature range from −180 to 300℃,and can carry out solar-blind UV optical communication in this range.In addition,the 4×4 array H-TPVD demonstrates clear optical imaging.These results make it possible for H-TPVD to expand its potential application scenarios.展开更多
Through tailoring interfacial chemistry,electrolyte engineering is a facile yet effective strategy for highperformance lithium(Li)metal batteries,where the solvation structure is critical for interfacial chemistry.Her...Through tailoring interfacial chemistry,electrolyte engineering is a facile yet effective strategy for highperformance lithium(Li)metal batteries,where the solvation structure is critical for interfacial chemistry.Herein,the effect of electrostatic interaction on regulating an anion-rich solvation is firstly proposed.The moderate electrostatic interaction between anion and solvent promotes anion to enter the solvation sheath,inducing stable solid electrolyte interphase with fast Li+transport kinetics on the anode.This asdesigned electrolyte exhibits excellent compatibility with Li metal anode(a Li deposition/stripping Coulombic efficiency of 99.3%)and high-voltage LiCoO_(2) cathode.Consequently,the 50μm-thin Li||high-loading LiCoO_(2) cells achieve significantly improved cycling performance under stringent conditions of high voltage over 4.5 V,lean electrolyte,and wide temperature range(-20 to 60℃).This work inspires a groundbreaking strategy to manipulate the solvation structure through regulating the interactions of solvent and anion for highperformance Li metal batteries.展开更多
This study presents the performance of a new single-stage scroll compressor used for the heat pump drying of thermally sensitive materials over a wide temperature range. The performance of the new compressor was predi...This study presents the performance of a new single-stage scroll compressor used for the heat pump drying of thermally sensitive materials over a wide temperature range. The performance of the new compressor was predicted by an ARI standard 540 map-based compressor model and verified by a semi-open drying heat pump system constructed for this purpose. A comparison of the experimental data with the predicted data proved that the new scroll compressor used in the drying heat pump works well, can supply a wide range of condensing temperatures （30--80℃） （without auxiliary heating）, and has a minimum coeffi- cient of performance （COP） above 2.0, even in the worst condition.展开更多
Many shape memory alloys can support large recoverable strains of a few percent by reversible stressinduced martensite transformation,yet they behave non-linear within a narrow operating temperature ra nge.Developing ...Many shape memory alloys can support large recoverable strains of a few percent by reversible stressinduced martensite transformation,yet they behave non-linear within a narrow operating temperature ra nge.Developing the bulk metallic materials with ultra-large linear elasticity over a wide tempe rature range has proven to be difficult.In this work,a material design concept was proposed,that is true elastic deformation and reversible twinning-detwinning deformation run in parallel to overcome this challe nge.By engineering the residual internal stress to realize the concurrency of true elastic deformation and twinning-detwinning deformation,a bulk nanocrystalline NiTi that possesses an ultra-large linear elastic strain up to 5.1 % and a high yield stress of 2.16 GPa over a wide temperature range of 270℃ was developed.This study offers a new avenue for developing the metallic materials with ultra-large linear elasticity over a wide temperature range of 270℃(from 70℃ to-197℃).展开更多
Electroabsorption modulators combining Franz-Keldysh effect and quantum confined Stark effect have been mono-lithically integrated with tunnel-injection quantum-well distributed feedback lasers using a quantum well in...Electroabsorption modulators combining Franz-Keldysh effect and quantum confined Stark effect have been mono-lithically integrated with tunnel-injection quantum-well distributed feedback lasers using a quantum well intermixing method. Superior characteristics such as extinction ratio and temperature insensitivity have been demonstrated at wide temperature ranges.展开更多
基金supported by the National Natural Science Foundation of China (NSFC-22209147)。
文摘High-temperature proton exchange membrane fuel cells(HT-PEMFC) possess distinct technical advantages of high output power, simplified water/heat management, increased tolerance to fuel impurities and diverse fuel sources, within the temperature range of 120–200 ℃. However, for practical automobile applications, it was crucial to broaden their low-temperature operating window and enable cold start-up capability. Herein, gel-state phosphoric acid(PA) doped sulfonated polybenzimidazole(PBI) proton exchange membranes(PEMs) were designed and synthesized via PPA sol-gel process and in-situ sultone ring-opening reactions with various proton transport pathways based on absorbed PA, flexible alkyl chain connected sulfonic acid groups and imidazole sites. The effects of flexible alkyl sulfonic acid side chain length and content on PA doping level, proton conductivity, and membrane stability under different temperature and relative humidity(RH) were thoroughly investigated. The prepared gel-state membranes contained a self-assembled lamellar and porous structure that facilitated the absorption of a large amount of PA with rapid proton transporting mechanisms. At room temperature, the optimized membrane exhibited a proton conductivity of 0.069 S cm^(-1), which was further increased to 0.162 and 0.358 S cm^(-1)at 80 and 200 ℃, respectively, without additional humidification. The most significant contribution of this work was demonstrating the feasibility of gel-state sulfonated PBI membranes in expanding HT-PEMFC application opportunities over a wider operating range of 25 to 240 ℃.
基金the Innovation-Driven Project of Central South University(2019CX033)the National Natural Science Foundation of China(51904344 and 52172264)the Natural Science Foundation of Hunan Province of China(2021JJ10060 and 2022GK2033)。
文摘The electrolyte integrated with lithium metal anodes is subjected to the issues of interfacial compatibility and stability,which strongly influence the performances of high-energy lithium metal batteries.Here,we report a new electrolyte recipe viz.a moderately concentrated electrolyte comprising of 2.4 M lithium bis(fluorosulfonyl)imide(LiFSI)in a cosolvent mixture of fluorinated ethylene carbonate(FEC)and dimethyl carbonate(DMC)with relatively high ion conductivity.Owing to the preferential decomposition of LiFSI and FEC,an inorganic-rich interphase with abundant Li_(2)O and LiF nanocrystals is formed on lithium metal with improved robustness and ion transfer kinetics,enabling lithium plating/stripping with an extremely low overpotential of~8 mV and the average CE of 97%.When tested in Li||LiFePO_(4) cell,this electrolyte provides long-term cycling with a capacity retention of 98.3%after 1000 cycles at 1 C and an excellent rate performance of 20 C,as well as an areal capacity of 1.35 mA h cm^(-2)at the cathode areal loading of 9 mg cm^(-2).Moreover,the Li||LiFePO_(4) cell exhibits excellent wide-temperature performances(-40~60℃),including long-term cycling stability over 2600 cycles without visible capacity fading at 0℃,as well as extremely high average CEs of 99.6%and 99.8% over 400 cycles under-20℃ and 45℃.
基金financially supported by the National Natural Science Foundation for Excellent Young Scholars of China (No. 51522402)the National Postdoctoral Program for Innovative Talents of China (No. BX20180034)+2 种基金the National Natural Science Foundation of China (No. 51902020)the Fundamental Research Funds for the Central Universities (No. FRF-TP-18-045A1)the China Postdoctoral Science Foundation (No. 2018M641192)
文摘Currently,developing supercapacitors with robust cycle stability and suitability for wide-temperature-range operations is still a huge challenge.In the present work,few-layer hexagonal boron nitride nanosheets(h-BNNSs)with a thickness of 2−4 atomic layers were fabricated via vacuum freeze-drying and nitridation.Then,the h-BNNSs/reduced graphene oxide(rGO)composite were further prepared using a hydrothermal method.Due to the combination of two two-dimensional(2D)van der Waals-bonded materials,the as-prepared h-BNNSs/rGO electrode exhibited robustness to wide-temperature-range operations from−10 to 50℃.When the electrodes worked in a neutral aqueous electrolyte(1 M Na2SO4),they showed a great stable cycling performance with almost 107%reservation of the initial capacitance at 0℃ and 111% at 50℃ for 5000 charge−discharge cycles.
基金supported by the National Key Research and Development Program of China(2019YFC1904500)National Natural Science Foundation of China(Nos.21801251,51502036,and 21875037)+2 种基金Young Top Talent of Fujian Young Eagle Program of Fujian Province,Educational Commis-sion of Fujian Province(2022G02022)Natural Science Foundation of Fuzhou City(2022-Y-004)Natural Science Foundation of Fujian Province(2023J02013).
文摘Aqueous rechargeable batteries are safe and environmentally friendly and can be made at a low cost;as such,they are attracting attention in the field of energy storage.However,the temperature sensitivity of aqueous batteries hinders their practical application.The solvent water freezes at low temperatures,and there is a reduction in ionic conductivity,whereas it evaporates rapidly at high temperatures,which causes increased side reactions.This review discusses recent progress in improving the performance of aqueous batteries,mainly with respect to electrolyte engineering and the associated strategies employed to achieve such improvements over a wide temperature domain.The review focuses on fi ve electrolyte engineer-ing(aqueous high-concentration electrolytes,organic electrolytes,quasi-solid/solid electrolytes,hybrid electrolytes,and eutectic electrolytes)and investigates the mechanisms involved in reducing the solidifi cation point and boiling point of the electrolyte and enhancing the extreme-temperature electrochemical performance.Finally,the prospect of further improving the wide temperature range performance of aqueous rechargeable batteries is presented.
基金Project(2013JSJJ027)supported by the Teacher Research Fund of Central South University,China
文摘To achieve good performance for LiFePO4-based batteries operated at a wide temperature range,mixed salts of LiBF4 LiBOB（lithium bis（oxalato）borate） and LiTFSI（lithium bis（trifluoromethanesulfonyl）imide）-LiBOB were investigated as alternative lithium salts to LiPF6 in non-aqueous electrolytes.LiFePO4/Li half cells using LiPF6,LiBF4-LiBOB and LiTFSI-LiBOB slats as lithium salts were investigated by galvanostatic cycling,cyclic voltammetry,thermogravimetric analysis.The results show that LiBF4-LiBOB and LiTFSI-LiBOB mixed salts are much more thermally stable than LiPF6.Corrosion of Al foil in the LiTFSI-based electrolytes can be suppressed successfully by the addition of LiBOB as a co-salt.The electrochemical performance of LiBF4-LiBOB and LiTFSI-LiBOB mixed salts based cells are both better than that of LiPF6-based cell.LiTFSI-LiBOB mixed salt based electrolyte is considered to be a very promising electrolyte candidate for Li-ion batteries that will be used in wide-temperature applications.
基金supported by the National Key Research and Development Program of China(Nos.2018YFA0208402 and 2020YFA0714700)the National Natural Science Foundation of China(Nos.52172060,51820105002,11634014,and 51372269)X.J.W.thanks Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2020005).
文摘Transparent photovoltaic devices(TPVDs)have attracted increasing attention in emerging electronic devices.As the application scenarios extend,there raise higher requirements regarding the stability and operating temperature range of TPVDs.In this work,a unique preparation strategy is proposed for air stable TPVD with a wide operating temperature range,i.e.,a nanoscale architecture termed as H-TPVD is constructed that integrates a free-standing and highly transparent conductive hybrid film of graphene and single-walled carbon nanotubes(G-SWNT TCF for short)with a metal oxide NiO/TiO_(2)heterojunction.The preparation approach is suitable for scaling up.Thanks to the excellent transparent conductivity of the freestanding G-SWNT hybrid film and the ultrathin NiO/TiO_(2)heterojunction(100 nm),H-TPVD selectively absorbs the ultraviolet(UV)band of sunlight and has a transparency of up to 71%in the visible light.The integrated nanoscale architecture manifests the significant holecollecting capability of the G-SWNT hybrid film and the efficient carrier generation and separation within the ultrathin NiO/TiO_(2)heterojunction,resulting in excellent performance of the H-TPVD with a specific detectivity of 2.7×10^(10) Jones.Especially,the freestanding G-SWNT TCF is a super stable and non-porous two-dimensional film that can insulate gas molecules,thereby protecting the surface properties of NiO/TiO_(2)heterojunctions and enhancing the stability of H-TPVD.Having subjected to 20,000 cycles and storage in air for three months,the performance parameters such as photo-response signal,output power,and specific detectivity show no noticeable degradation.In particular,the as-fabricated self-powered H-TPVD can operate over a wide temperature range from −180 to 300℃,and can carry out solar-blind UV optical communication in this range.In addition,the 4×4 array H-TPVD demonstrates clear optical imaging.These results make it possible for H-TPVD to expand its potential application scenarios.
基金supported by National Nature Science Foundation of China(No.51872157 and No.52072208)National Key R&D Program of China 2021YFA1202802Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01N111)。
文摘Through tailoring interfacial chemistry,electrolyte engineering is a facile yet effective strategy for highperformance lithium(Li)metal batteries,where the solvation structure is critical for interfacial chemistry.Herein,the effect of electrostatic interaction on regulating an anion-rich solvation is firstly proposed.The moderate electrostatic interaction between anion and solvent promotes anion to enter the solvation sheath,inducing stable solid electrolyte interphase with fast Li+transport kinetics on the anode.This asdesigned electrolyte exhibits excellent compatibility with Li metal anode(a Li deposition/stripping Coulombic efficiency of 99.3%)and high-voltage LiCoO_(2) cathode.Consequently,the 50μm-thin Li||high-loading LiCoO_(2) cells achieve significantly improved cycling performance under stringent conditions of high voltage over 4.5 V,lean electrolyte,and wide temperature range(-20 to 60℃).This work inspires a groundbreaking strategy to manipulate the solvation structure through regulating the interactions of solvent and anion for highperformance Li metal batteries.
基金supported by the National High Technology Research and Development Program of China(Grant No.2012AA10A510)
文摘This study presents the performance of a new single-stage scroll compressor used for the heat pump drying of thermally sensitive materials over a wide temperature range. The performance of the new compressor was predicted by an ARI standard 540 map-based compressor model and verified by a semi-open drying heat pump system constructed for this purpose. A comparison of the experimental data with the predicted data proved that the new scroll compressor used in the drying heat pump works well, can supply a wide range of condensing temperatures （30--80℃） （without auxiliary heating）, and has a minimum coeffi- cient of performance （COP） above 2.0, even in the worst condition.
基金supported by the National Key R&D Program of China (No. 2018YFB1105100)the National Natural Science Foundation of China (Nos. 51971244 and 51731010)+3 种基金the Science Foundation of China University of Petroleum, Beijing (No. 2462018BJC005)the Pre-research Program of Frontier Science, Ministry of Education (No. 6141A020222)the Research Fund of China Manned Space Engineering (No. 040201)supported by the US Department of Energy, Office of Science, and Office of Basic Energy Science (No. DE-AC02-06CH11357)。
文摘Many shape memory alloys can support large recoverable strains of a few percent by reversible stressinduced martensite transformation,yet they behave non-linear within a narrow operating temperature ra nge.Developing the bulk metallic materials with ultra-large linear elasticity over a wide tempe rature range has proven to be difficult.In this work,a material design concept was proposed,that is true elastic deformation and reversible twinning-detwinning deformation run in parallel to overcome this challe nge.By engineering the residual internal stress to realize the concurrency of true elastic deformation and twinning-detwinning deformation,a bulk nanocrystalline NiTi that possesses an ultra-large linear elastic strain up to 5.1 % and a high yield stress of 2.16 GPa over a wide temperature range of 270℃ was developed.This study offers a new avenue for developing the metallic materials with ultra-large linear elasticity over a wide temperature range of 270℃(from 70℃ to-197℃).
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60736036,60706009,60777021 and 60702006)the National Basic Research Program of China (Grant Nos. 2006CB604901 and 2006CB604902)the National High Technology Research and Development Program of China (Grant Nos. 2007AA03Z419,2007AA03Z417 and 2009AA03Z442)
文摘Electroabsorption modulators combining Franz-Keldysh effect and quantum confined Stark effect have been mono-lithically integrated with tunnel-injection quantum-well distributed feedback lasers using a quantum well intermixing method. Superior characteristics such as extinction ratio and temperature insensitivity have been demonstrated at wide temperature ranges.
