Stable Lithium-Carbon Composite Enabled by Dual-Salt Additives

• 作者: Lei Zheng Feng Guo Tuo Kang Yingzhu Fan Wei Gu Yayun Mao Ya Liu Rong Huang Zhiyun Li Yanbin Shen Wei Lu Liwei Chen
• 来源期刊: 纳微快报（英文版）
• 年，卷（期）: 2021,（7）
• 页码范围: 127-137
• 页数: 11页
• 语种: 英文

摘要

Lithium metal is regarded as the ultimate negative elec-trode material for secondary batteries due to its high energy density.However,it suffers from poor cycling stability because of its high reac-tivity with liquid electrolytes.Therefore,continuous efforts have been put into improving the cycling Coulombic efficiency(CE)to extend the lifespan of the lithium metal negative electrode.Herein,we report that using dual-salt additives of LiPF6 and LiNO3 in an ether solvent-based electrolyte can significantly improve the cycling stability and rate capabil-ity of a Li-carbon(Li-CNT)composite.As a result,an average cycling CE as high as 99.30％ was obtained for the Li-CNT at a current density of 2.5 mA cm-2 and an negative electrode to positive electrode capacity(N/P)ratio of 2.The cycling stability and rate capability enhancement of the Li-CNT negative electrode could be attributed to the formation of a better solid electrolyte interphase layer that contains both inorganic components and organic polyether.The former component mainly originates from the decomposition of the LiNO3 additive,while the latter comes from the LiPF6-induced ring-opening polymerization of the ether solvent.This novel surface chemistry significantly improves the CE of Li negative electrode,revealing its importance for the practical application of lithium metal batteries.