Comparative Study of Lithium-Rich Cathode in Ester- and Ether-Based Localized High-Concentration Electrolytes

Abstract

Lithium-rich manganese oxide (LRMO)-based lithium metal batteries (LRMO-LMBs) are prospective options for future electrochemical storage systems. The performance of the LRMO-LMBs is significantly influenced by the electrolyte. The comprehension of the correlation between electrolyte formulation and electrode stability is crucial in guiding the design of advanced electrolytes for enhancing cell performance. Herein, we systematically study the interfacial behavior of localized high-concentration electrolytes (LHCEs) and their effect on cathode stability in the Li||LRMO system, selecting typical LHCEs using 1,2-dimethoxyethane (DME) and dimethyl carbonate (DMC) solvents. On the LRMO surface, DME-LHCE tends to undergo uncontrollable oxidation at 4.8 V, which leads to severe structural degradation of LRMO. Moreover, it causes increased dissolution of transition metal ions that subsequently deposit on the Li metal anode, thereby accelerating anode failure. Conversely, DMC-LHCE forms more stable electrode/electrolyte interphases, which effectively protect both the cathode and anode. Consequently, the Li||LRMO cell using DMC-LHCE shows excellent cycling performance, maintaining 96.6% capacity retention over 100 cycles at 0.5 C. This study offers insights into the compatibility between LHCEs and LRMO, facilitating electrolyte design for LRMO-LMBs.