优化Li||NCM811电池电解液溶剂化和电极电解液界面的阴离子受体添加剂策略  

Anion-Acceptor Electrolyte Additive Strategy for Optimizing Electrolyte Solvation Characteristics and Electrode Electrolyte Interphases for Li||NCM811 Battery

作　　者：刘建东 李鑫 吴达雄 王华平 黄俊达 马建民 Jiandong Liu;Xin Li;Daxiong Wu;Huaping Wang;Junda Huang;Jianmin Ma(School of Physics and Electronics,Hunan University,Changsha 410082,China;School of Chemistry,Tiangong University,Tianjin 300387,China.)

机构地区：[1]湖南大学物理与微电子科学学院,长沙410082 [2]天津工业大学化学学院,天津300387

出　　处：《物理化学学报》2024年第6期57-59,共3页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(51971090,U21A20311)资助项目。

摘　　要：锂金属电池的循环稳定性和倍率能力受制于多个因素,如阳极/阴极电解液界面的品质和电解液溶剂化特性。在该工作中,我们提出了阴离子受体电解液添加剂策略,通过六氟苯添加剂对Li^(+)溶剂化结构进行调控,实现了PF_(6)^(-)的稳定性并提高了电解液的导电性,优化了阳极/阴极电解液界面中间相的组分/结构特征,有效抑制了锂枝晶的生长和提升了阴极表面的Li^(+)传输,Li||Li对称电池在1m A·cm^(-2)的电流密度下实现超过400h的稳定循环,并且Li||NCM811电池在200m A·g^(-1)的电流密度下经过100次循环后的容量保持率达到75%。Metallic lithium(Li) offers Li metal batteries(LMBs) with an opportunity to meet the high-energy demand in many fields.At present,the main cathode materials used for high-energy-density batteries are nickel-rich layered oxides,including nickel cobalt lithium manganese oxides(NCM) with intercalation chemistry.According to this plan,NMC811 demonstrates great merits in this aspect.However,there are still many problems with Li metal anode.The failure of Li anode is mainly caused by the high reactivity of Li metal,which can cause irreversible continuous reactions between Li and electrolyte to shorten cycling life.Due to multiple electroplating and stripping processes,Li anode undergoes significant volume and morphology change,increasing side reactions and the growth of Li dendrites caused by the first two factors.Electrolyte engineering,as a simple and effective modification method,can effectively solve the above problems.Among them,using electrolyte additives is a simple,efficient,and economical electrolyte engineering strategy.Herein,we proposed an anion acceptor electrolyte additive strategy for optimizing the component/structural characteristics of solid/cathode electrolyte interphases to inhibit the growth of Li dendrites and Li^(+) transition on cathode surface for enhancing cycling and rate performance of Li|| NCM811 battery,which is also ascribed to the regulation of Li+ solvation structure by hexafluorobenzene(HFBen) to realizing the stability of PF_(6)^(-) and the conductivity enhancement of electrolyte.As expected,Li||Li cells with 1%(wt) HFBen-contained electrolyte could achieve a stable cycling above 400 h at 1 m A·cm^(-2),and the capacity retention rate of Li||NCM811 battery could reach 75% after 100 cycles at 200 m A·g^(-1).Finally,the cycling and rate performance of Li||NMC811 batteries were significantly enhanced at 4.5 V with the help of HFBen.This work demonstrates that HFBen as an additive can effectively improve the electrochemical performance of LMBs.Moreover,the interfacial reaction mechanism

关 键 词：电解液 六氟苯 阴离子受体 锂金属电池 锂阳极 阳极/阴极电解质界面 

分 类 号：O646[理学—物理化学]