A Single-Layer Piezoelectric Composite Separator for Durable Operation of Li Metal Anode at High Rates

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外文摘要：Piezoelectric ceramic and polymeric separators have been proposed to effectively regulate Li deposition and suppress dendrite growth,but such separators still fail to satisfactorily support durable operation of lithium metal batteries owing to the fragile ceramic layer or low-piezoelectricity polymer as employed.Herein,by combining PVDF-HFP and ferroelectric BaTiO3,we develop a homogeneous,single-layer composite separator with strong piezoelectric effects to inhibit dendrite growth while maintaining high mechanical strength.As squeezed by local protrusion,the polarized PVDF-HFP/BaTiO3 composite separator generates a local voltage to suppress the local-intensified electric field and further deconcentrate regional lithium-ion flux to retard lithium deposition on the protrusion,hence enabling a smoother and more compact lithium deposition morphology than the unpoled composite separator and the pure PVDF-HFP separator,especially at high rates.Remarkably,the homogeneous incorporation of BaTiO3 highly improves the piezoelectric performances of the separator with residual polarization of 0.086 pC cm-2 after polarization treatment,four times that of the pure PVDF-HFP separator,and simultaneously increases the transference number of lithium-ion from 0.45 to 0.57.Beneficial from the prominent piezoelectric mechanism,the polarized PVDF-HFP/BaTiO3 composite separator enables stable cyclic performances of Li||LiFePO4 cells for 400 cycles at 2 C(1 C=170 mA g-1)with a capacity retention above 99％,and for 600 cycles at 5 C with a capacity retention over 85％.

外文关键词：

composite separatorLi metal anodespiezoelectric materialsPVDF-HFPuniform Li deposition

作者：

Yuanpeng Ji、Botao Yuan、Jiawei Zhang、Zhezhi Liu、Shijie Zhong、Jipeng Liu、Yuanpeng Liu、Mengqiu Yang、Changguo Wang、Chunhui Yang、Jiecai Han、Weidong He

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作者单位：

National Key Laboratory of Science and Technology on Advanced Composites in Special Environments,and Center for Composite Materials and Structures,Harbin Institute of Technology,Harbin 150080,China

MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage,School of Chemistry and Chemical Engineering,Harbin Institute of Technology,Harbin 150080,China

National Key Laboratory of Science and Technology on Advanced Composites in Special Environments and Center for Composite Materials and Structures,Harbin Institute of Technology,Harbin,150080,China

School of Petroleum Engineering Chongqing University of Science and Technology,Chongqing 401331,China

State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology,Harbin 150080,China

Chongqing Research Institute,Harbin Institute of Technology,Chongqing 401151,China

School of Mechanical Engineering,Chengdu University,Chengdu 610106,China

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出版年：

2024

DOI：

10.1002/eem2.12510

能源与环境材料(英文)

ISSN：

年,卷(期)：2024.7(1)