电解质
阳极
材料科学
溶剂
溶剂化
化学工程
石墨
离子电导率
无机化学
有机化学
化学
物理化学
电极
复合材料
工程类
作者
Yongxin Ma,Minghao Huang,Yunfei Xue,Xiaolong Wu,W. Kong,Y. Zhou,Heng Zhang,Hongfa Xiang,Yunhui Huang
标识
DOI:10.1021/acsami.4c03149
摘要
Graphite anode suffers from great capacity loss and larger cell polarization under low-temperature conditions in lithium-ion batteries (LIBs), which are mainly caused by the high energy barrier for the Li+ desolvation process and sluggish Li+ transfer rate across the solid electrolyte interface (SEI). Regulating an electrolyte with an anion-dominated solvation structure could synchronously stabilize the interface and boost the reaction kinetics of the graphite anode. Herein, a highly ionic conductive electrolyte consisting of a fully methylated cyclic ether solvent of 2,2,4,4,5,5-hexamethyl-1,3-dioxolane (HMD) and fluoroethylene carbonate (FEC) cosolvent was designed. The high electron-donating effect and steric hindrance of −(CH3)2 in HMD endow the HMD-based electrolyte with high ionic conductivity but lower coordination numbers with Li+, and an anion-dominated solvation structure was formed. Such configuration can accelerate the desolvation process and induce the forming of a LiF-rich SEI film on the anode, avoiding the solvent coembedding into graphite and enhancing the ion migration rate under low temperatures. The assembled Li||graphite cell with the tame electrolyte outperformed the conventional carbonates-based cell, showing 93.8% capacity retention after 227 cycles for the DF-based cell compared to 64.7% after 150 cycles. It also exhibited a prolonged cycle life for 200 rounds with 81% capacity retention under −20 °C. Therefore, this work offers a valuable thought for solvent design and provides approaches to electrolyte design for low-temperature LIBs.
科研通智能强力驱动
Strongly Powered by AbleSci AI