Organic-Inorganic Hybrid SEI Induced by a New Lithium Salt for High-Performance Metallic Lithium Anodes

Leyi Guo; Feifei Huang; Muzhi Cai; Junjie Zhang; Guoqiang Ma; Shiqing Xu

doi:10.1021/acsami.1c04788

Organic-Inorganic Hybrid SEI Induced by a New Lithium Salt for High-Performance Metallic Lithium Anodes

ACS Appl Mater Interfaces. 2021 Jul 21;13(28):32886-32893. doi: 10.1021/acsami.1c04788. Epub 2021 Jul 12.

Authors

Leyi Guo¹, Feifei Huang², Muzhi Cai², Junjie Zhang², Guoqiang Ma^{2

3}, Shiqing Xu²

Affiliations

¹ College of Materials and Chemistry, China Jiliang University, Hangzhou 310018, China.
² Institute of Optoelectronic Materials and Devices, China Jiliang University, Hangzhou 310018, China.
³ Zhejiang Research Institute of Chemical Industry, Hangzhou 310023, China.

PMID: 34251193
DOI: 10.1021/acsami.1c04788

Abstract

The practical application of the metallic lithium anode is suppressed by the highly unstable interface between electrolytes and lithium metal during the process of lithium plating/stripping. A perfect solid electrolyte interphase (SEI) can inhibit detrimental parasitic reactions, thereby improving the cycling performance of the metallic lithium anode. In this work, a high-purity solid lithium difluorobis(oxalato) phosphate (LiDFOP) is synthesized and an outstanding organic-inorganic hybrid SEI is obtained in an ether-based electrolyte for the first time induced by LiDFOP. The preferential reduction of LiDFOP can form an SEI rich in LiF and Li_xPO_yF_z species, thereby improving the conductivity and stability of the SEI. In addition, cationic-induced ring-opening polymerization between LiDFOP and 1,3-dioxolane endows the SEI with excellent adaptability to the reiterative volume change of the metallic lithium anode. Therefore, the Li/Cu battery maintains a high coulombic efficiency of 98.37% at a current density of 2 mA/cm² for 200 cycles, and the Li/Li symmetrical battery shows stable voltage hysteresis over 1000 h even under the condition of 5 mA/cm². The Li/S battery fabricated employing the electrolyte with LiDFOP shows significant improvement of cycling performance as well. These results manifest that the formation of an organic-inorganic hybrid SEI from LiDFOP can be employed as a new strategy to overcome the problem from the unstable SEI in metallic lithium batteries.

Keywords: Li/S battery; electrolyte additive; lithium dendrites; lithium difluorobis(oxalato) phosphate; metallic lithium anode; solid electrolyte interphase.