Enabling rechargeable Li‐MnO2 batteries using ether electrolytes

Abstract

A low‐carbon future demands more affordable batteries utilizing abundant elements with sustainable end‐of‐life battery management. Despite the economic and environmental advantages of Li‐MnO2 batteries, their application so far has been largely constrained to primary batteries. Here, we demonstrate that one of the major limiting factors preventing the stable cycling of Li‐MnO2 batteries, Mn dissolution, can be effectively mitigated by employing a common ether electrolyte, 1 mol/L lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in 1,3‐dioxane (DOL)/1,2‐dimethoxyethane (DME). We discover that the suppression of this dissolution enables highly reversible cycling of the MnO2 cathode regardless of the synthesized phase and morphology. Moreover, we find that both the LiPF6 salt and carbonate solvents present in conventional electrolytes are responsible for previous cycling challenges. The ether electrolyte, paired with MnO2 cathodes is able to demonstrate stable cycling performance at various rates, even at elevated temperature such as 60°C. Our discovery not only represents a defining step in Li‐MnO2 batteries with extended life but provides design criteria of electrolytes for vast manganese‐based cathodes in rechargeable batteries.