In this study,commercial copper(Cu)foil and Cu foam are used as the working electrodes to systematically investigate the electrochemical deposition and dissolution processes of metallic lithium(Li)on these electrodes;...In this study,commercial copper(Cu)foil and Cu foam are used as the working electrodes to systematically investigate the electrochemical deposition and dissolution processes of metallic lithium(Li)on these electrodes;Li metal deposited on the Cu foil electrode is porous and loose.The surface solid electrolyte interface(SEI)film after dissolution from Li dendrites maintains a dendritic porous structure,resulting in a large volume effect of the electrode during the cycle.The Cu foam electrode provides preferential nucleation and deposition sites near the side surface of the separator;the difference in Li affinity results in a heterogeneous deposition and dendrite growth of metallic Li.展开更多
Technical breakthrough of composite polymer electrolyte(CPE)is one of the key factors that determines the commercial process of the current solid-state lithium battery.However,high interface impedance limits its elect...Technical breakthrough of composite polymer electrolyte(CPE)is one of the key factors that determines the commercial process of the current solid-state lithium battery.However,high interface impedance limits its electrochemical performances.It is crucial to optimize the design of multiphase interfaces among different components in CPE for regulating Li+transport.Herein,a multi-affinity self-assembled 12-crown-4-TFSI(12C4-TFSI)supramolecular nanolayer is introduced into poly(vinylidene difluoride)-Li_(6.75)La_(3)Zr_(1.75)Ta_(0.25)O_(12)(PVDF-LLZTO)CPE as interface modifier.As a result,enhanced Li+conductivity of 4.29×10^(-4)S·cm^(-1),Li+transfer number of 0.44,and stable electrochemical window voltage of 4.8 V vs.Li/Li+at 30℃ are obtained.The symmetric Li||Li cell exhibits an improved critical current density(CCD)of 1.2 mA·cm^(-2) and steady cycling at 0.2 mA·cm^(-2) for over 850 h without visible voltage fluctuation.The assembled LiǁLiFePO4 coin solid-state cell delivers a high initial discharge capacity of 172.9 mAh·g^(-1) at 0.1 C,rate capability(up to 5.0 C)and outstanding cycling stability with a capacity retention of 87.2% after over 750 cycles at 1.0 C.The associated LiǁLiFePO4 pouch cell presents an initial specific discharge capacity of 112.3 mAh·g−1 and successfully runs 30 cycles with a final capacity of 101.8 mAh·g^(-1).This work offers a facile strategy to optimize multiphase interfaces of PVDF-LLZTO CPE for stable solid-state lithium battery.展开更多
基金the National Natural Science Foundation of China(No.51874361)the National Natural Science Foundation of China Youth Fund(51904343)for supporting this work.
文摘In this study,commercial copper(Cu)foil and Cu foam are used as the working electrodes to systematically investigate the electrochemical deposition and dissolution processes of metallic lithium(Li)on these electrodes;Li metal deposited on the Cu foil electrode is porous and loose.The surface solid electrolyte interface(SEI)film after dissolution from Li dendrites maintains a dendritic porous structure,resulting in a large volume effect of the electrode during the cycle.The Cu foam electrode provides preferential nucleation and deposition sites near the side surface of the separator;the difference in Li affinity results in a heterogeneous deposition and dendrite growth of metallic Li.
基金We gratefully acknowledge the financial support of the National Key Research and Development Program of China(No.2021YFE0107200)the National Natural Science Foundation of China(No.21773167)the Key R&D Project funded by Department of Science and Technology of Jiangsu Province(No.BE2020003).
文摘Technical breakthrough of composite polymer electrolyte(CPE)is one of the key factors that determines the commercial process of the current solid-state lithium battery.However,high interface impedance limits its electrochemical performances.It is crucial to optimize the design of multiphase interfaces among different components in CPE for regulating Li+transport.Herein,a multi-affinity self-assembled 12-crown-4-TFSI(12C4-TFSI)supramolecular nanolayer is introduced into poly(vinylidene difluoride)-Li_(6.75)La_(3)Zr_(1.75)Ta_(0.25)O_(12)(PVDF-LLZTO)CPE as interface modifier.As a result,enhanced Li+conductivity of 4.29×10^(-4)S·cm^(-1),Li+transfer number of 0.44,and stable electrochemical window voltage of 4.8 V vs.Li/Li+at 30℃ are obtained.The symmetric Li||Li cell exhibits an improved critical current density(CCD)of 1.2 mA·cm^(-2) and steady cycling at 0.2 mA·cm^(-2) for over 850 h without visible voltage fluctuation.The assembled LiǁLiFePO4 coin solid-state cell delivers a high initial discharge capacity of 172.9 mAh·g^(-1) at 0.1 C,rate capability(up to 5.0 C)and outstanding cycling stability with a capacity retention of 87.2% after over 750 cycles at 1.0 C.The associated LiǁLiFePO4 pouch cell presents an initial specific discharge capacity of 112.3 mAh·g−1 and successfully runs 30 cycles with a final capacity of 101.8 mAh·g^(-1).This work offers a facile strategy to optimize multiphase interfaces of PVDF-LLZTO CPE for stable solid-state lithium battery.
