The lithium-sulfur battery is the subject of much recent attention due to the high theoretical energy density,but practical applications are challenged by fast decay owing to polysulfide shuttle and electrode architec...The lithium-sulfur battery is the subject of much recent attention due to the high theoretical energy density,but practical applications are challenged by fast decay owing to polysulfide shuttle and electrode architecture degradation.A comprehensive study of the sulfur host microstructure design and the cell architecture construction based on the MXene phase(Ti3C2Tx nanosheets) is performed,aiming at realize stable cycling performance of Li-S battery with high sulfur areal loading.The interwoven KB@Ti3C2Tx composite formed by self-assembly of MXene and Ktej en black,not only provides superior conductivity and maintains the electrode integrality bearing the volume expansion/shrinkage when used as the sulfur host,but also functions as an interlayer on separator to further retard the polysulfide cross-diffusion that possibly escaped from the cathode.The KB@Ti3C2Tx interlayer is only 0.28 mg cm-2 in areal loading and 3 μm in thickness,which accounts a little contribution to the thick sulfur electrode;thus,the impacts on the energy density is minimal.By coupling the robust KB@Ti3C2Tx cathode and the effective KB@Ti3C2Tx modified separator,a stable Li-S battery with high sulfur areal loading(5.6 mg cm-2) and high areal capacity(6.4 mAh cm-2) at relatively lean electrolyte is achieved.展开更多
The reversible storage of Zn^(2+)ions in Prussian blue analogues with typical aqueous solution was challenged by fast degradation and poor coulombic efficiency,while the mechanism is yet to be uncovered.This study cor...The reversible storage of Zn^(2+)ions in Prussian blue analogues with typical aqueous solution was challenged by fast degradation and poor coulombic efficiency,while the mechanism is yet to be uncovered.This study correlates the performance of the nickel hexacyanoferrate to the dynamics of H_(2)O in the electrolyte and the associated phase stability of the electrode.It demonstrates severe Ni dissolution in conventional diluted aqueous electrolyte(1 M ZnSO^(4)or 1 M Zn(TFSI)^(2)),leading to structure collapse with the formation of an electrochemical inert phase.This is regarded as the descriptor for the fast decay of nickel hexacyanoferrate in diluted aqueous electrolyte.However,a well-preserved open framework for zinc storage was obtained in concentrated aqueous electrolyte(1 M Zn(TFSI)_(2)+21 M LiTFSI)—the H_(2)O activity is highly suppressed by extensive coordination—thus,reversible capacity of 60.2 m Ah g^(-1)over 1600 cycles could be delivered.展开更多
Potassium-ion capacitors(KICs)are promising for sustainable and eco-friendly energy storage technologies,yet their slow reaction kinetics and poor cyclability induced by large K-ion size are a major obstacle toward pr...Potassium-ion capacitors(KICs)are promising for sustainable and eco-friendly energy storage technologies,yet their slow reaction kinetics and poor cyclability induced by large K-ion size are a major obstacle toward practical applications.Herein,by employing black phosphorus nanosheets(BPNSs)as a typical high-capacity anode material,we report that BPNS anodes armored with an ultrathin oriented-grown metal–organic-framework(MOF)interphase layer(BPNS@MOF)exhibit regulated potassium storage behavior for highperformance KICs.The MOF interphase layers as protective layer with ordered pores and high chemical/mechanical stability facilitate K ion diffusion and accommodate the volume change of electrode,beneficial for improved reaction kinetics and enhanced cyclability,as evidenced by substantial characterizations,kinetics analysis and DFT calculations.Consequently,the BPNS@MOF electrode as KIC anodes exhibits outstanding cycle performance outperforming most of the reported state-of-art KICs so far.展开更多
基金financially supported by National Key Research and Development Program(No.2019YFA0210600)the Major Technological Innovation Project of Hubei Science and Technology Department(No.2019AAA164)+1 种基金the National Natural Science Foundation of China(No.51972107)the Innovative Research Groups of Hunan Province(No.2019JJ10001)。
文摘The lithium-sulfur battery is the subject of much recent attention due to the high theoretical energy density,but practical applications are challenged by fast decay owing to polysulfide shuttle and electrode architecture degradation.A comprehensive study of the sulfur host microstructure design and the cell architecture construction based on the MXene phase(Ti3C2Tx nanosheets) is performed,aiming at realize stable cycling performance of Li-S battery with high sulfur areal loading.The interwoven KB@Ti3C2Tx composite formed by self-assembly of MXene and Ktej en black,not only provides superior conductivity and maintains the electrode integrality bearing the volume expansion/shrinkage when used as the sulfur host,but also functions as an interlayer on separator to further retard the polysulfide cross-diffusion that possibly escaped from the cathode.The KB@Ti3C2Tx interlayer is only 0.28 mg cm-2 in areal loading and 3 μm in thickness,which accounts a little contribution to the thick sulfur electrode;thus,the impacts on the energy density is minimal.By coupling the robust KB@Ti3C2Tx cathode and the effective KB@Ti3C2Tx modified separator,a stable Li-S battery with high sulfur areal loading(5.6 mg cm-2) and high areal capacity(6.4 mAh cm-2) at relatively lean electrolyte is achieved.
基金financial support provided by National Key Research and Development Program(No.2019YFA0210600)the National Natural Science Foundation of China(No.21905085+2 种基金No.51972107)the State Grid Shanghai Municipal Electric Power Company(No.B30970190001)the Innovative Research Groups of Hunan Province(No.2019JJ10001)
文摘The reversible storage of Zn^(2+)ions in Prussian blue analogues with typical aqueous solution was challenged by fast degradation and poor coulombic efficiency,while the mechanism is yet to be uncovered.This study correlates the performance of the nickel hexacyanoferrate to the dynamics of H_(2)O in the electrolyte and the associated phase stability of the electrode.It demonstrates severe Ni dissolution in conventional diluted aqueous electrolyte(1 M ZnSO^(4)or 1 M Zn(TFSI)^(2)),leading to structure collapse with the formation of an electrochemical inert phase.This is regarded as the descriptor for the fast decay of nickel hexacyanoferrate in diluted aqueous electrolyte.However,a well-preserved open framework for zinc storage was obtained in concentrated aqueous electrolyte(1 M Zn(TFSI)_(2)+21 M LiTFSI)—the H_(2)O activity is highly suppressed by extensive coordination—thus,reversible capacity of 60.2 m Ah g^(-1)over 1600 cycles could be delivered.
基金This work was financially supported by the National Natural Science Foundation(51972235)the Natural Science Foundation of Shanghai(17ZR1447800)+1 种基金Jiangsu Key R&D Plan(BE2018006-4)the Program for Professor of Special Appointment(Eastern Scholar)at the Shanghai Institutions of Higher Learning and the Fundamental Research Funds for the Central Universities.
文摘Potassium-ion capacitors(KICs)are promising for sustainable and eco-friendly energy storage technologies,yet their slow reaction kinetics and poor cyclability induced by large K-ion size are a major obstacle toward practical applications.Herein,by employing black phosphorus nanosheets(BPNSs)as a typical high-capacity anode material,we report that BPNS anodes armored with an ultrathin oriented-grown metal–organic-framework(MOF)interphase layer(BPNS@MOF)exhibit regulated potassium storage behavior for highperformance KICs.The MOF interphase layers as protective layer with ordered pores and high chemical/mechanical stability facilitate K ion diffusion and accommodate the volume change of electrode,beneficial for improved reaction kinetics and enhanced cyclability,as evidenced by substantial characterizations,kinetics analysis and DFT calculations.Consequently,the BPNS@MOF electrode as KIC anodes exhibits outstanding cycle performance outperforming most of the reported state-of-art KICs so far.
