摘要
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.
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).
