Stabilizing High-Nickel Cathodes via Interfacial Hydrogen Bonding Effects Using a Hydrofluoric Acid-Scavenging Separator

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外文摘要：Nickel-rich layered Li transition metal oxides are the most promising cathode materials for high-energy-density Li-ion batteries.However,they exhibit rapid capacity degradation induced by transition metal dissolution and structural reconstruction,which are associated with hydrofluoric acid(HF)generation from lithium hexafluorophosphate decomposition.The potential for thermal runaway during the working process poses another challenge.Separators are promising components to alleviate the aforementioned obstacles.Herein,an ultrathin double-layered separator with a 10 μm polyimide(PI)basement and a 2 μm polyvinylidene difluoride(PVDF)coating layer is designed and fabricated by combining a non-solvent induced phase inversion process and coating method.The PI skeleton provides good stability against potential thermal shrinkage,and the strong PI-PVDF bonding endows the composite separator with robust structural integrity;these characteristics jointly contribute to the extraordinary mechanical tolerance of the separator at elevated temperatures.Additionally,unique HF-scavenging effects are achieved with the formation of-CO… H-F hydrogen bonds for the abundant HF coordination sites pro-vided by the imide ring;hence,the layered Ni-rich cathodes are protected from HF attack,which ulti-mately reduces transition metal dissolution and facilitates long-term cyclability of the Ni-rich cathodes.Li||NCM811 batteries(where"NCM"indicates LiNixCoyMn1-x-yO2)with the proposed compos-ite separator exhibit a 90.6％capacity retention after 400 cycles at room temperature and remain sustain-able at 60 ℃ with a 91.4％capacity retention after 200 cycles.By adopting a new perspective on separators,this study presents a feasible and promising strategy for suppressing capacity degradation and enabling the safe operation of Ni-rich cathode materials.

外文关键词：

Nickel-rich cathodesComposite separatorHF scavengingTransition metal dissolutionLong-term cyclability

作者：

Shijie Zhong、Liwei Dong、Botao Yuan、Yueyao Dong、Qun Li、Yuanpeng Ji、Yuanpeng Liu、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,& Center for Composite Materials and Structures,Harbin Institute of Technology,Harbin 150080,China

Chongqing Research Institute,Harbin Institute of Technology,Chongqing 401151,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 150001,China

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

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基金：

Science Foundation of the National Key Laboratory of Science and Technology on Advanced Composites in Special EnvironmentsNatural Science Foundation of Chongqing,ChinaNatural Science Foundation of Chongqing,ChinaNatural Science Foundation of Chongqing,ChinaNatural Science Foundation of Chongqing,ChinaNatural Science Foundation of Chongqing,ChinaChongqing Technology Innovation and Application Development Special Key Project

项目编号：

CSTC2021jcyjmsxmX10305CSTB2022NSCQ-MSX0246CSTB2022NSCQ-MSX0242CSTB2022NSCQ-MSX1244CSTB2022NSCQ-MCSTB2023TIAD-KPX0010

出版年：

2024

DOI：

10.1016/j.eng.2023.09.025

工程(英文)

CSTPCDEI

ISSN：2095-8099

年,卷(期)：2024.39(8)