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

使用氢氟酸清除分离器通过界面氢键效应稳定高镍阴极

作　　者：Shijie Zhong Liwei Dong Botao Yuan Yueyao Dong Qun Li Yuanpeng Ji Yuanpeng Liu Jiecai Han Weidong He 

机构地区：[1]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 [2]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 [3]Chongqing Research Institute,Harbin Institute of Technology,Chongqing 401151,China [4]School of Mechanical Engineering,Chengdu University,Chengdu 610106,China

出　　处：《Engineering》2024年第8期117-126,共10页工程（英文）

基　　金：supported by the Science Foundation of the National Key Laboratory of Science and Technology on Advanced Composites in Special Environments.This work was sponsored by the Natural Science Foundation of Chongqing,China(CSTC2021jcyjmsxmX10305,CSTB2022NSCQ-MSX0246,CSTB2022NSCQMSX0242,CSTB2022NSCQ-MSX1244,CSTB2022NSCQ-MSX0441,CSTB2022NSCQ-MSX1356,CSTB2022NSCQ-MSX1572,CSTB2022 NSCQ-MSX1583,CSTB2022NSCQMSX0487,CSTB2022TFII-OFX0034,and CSTB2023TIAD-KPX0010);the Chongqing Technology Innovation and Application Development Special Key Project(CSTB2023TIAD-KPX0010).

摘　　要：Nickel-rich layered Li transition metal oxides are the most promising cathode materials for high-energydensity 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 lm polyimide(PI)basement and a 2 lm polyvinylidene difluoride(PVDF)coating layer is designed and fabricated by combining a nonsolvent 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 provided by the imide ring;hence,the layered Ni-rich cathodes are protected from HF attack,which ultimately reduces transition metal dissolution and facilitates long-term cyclability of the Ni-rich cathodes.Li||NCM811 batteries(where“NCM”indicates LiNi_(x)Co_(y)Mn_(1-x-y)O_(2))with the proposed composite separator exhibit a 90.6%capacity retention after 400 cycles at room temperature and remain sustainable 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.

关 键 词：Nickel-rich cathodes Composite separator HF scavenging Transition metal dissolution Long-term cyclability 

分 类 号：TB383.2[一般工业技术—材料科学与工程] TM912[电气工程—电力电子与电力传动]