In-situ synthesis of Mn2SiO4 and MnxSi dual phases through solid-state reaction to improve the initial Coulombic efficiency of SiO anode for Lithium-Ion batteries

Abstract

Silicon monoxide(SiO)-based anode materials have been extensively examined as high energy density for lithium-ion batteries, but still suffer from low initial Coulombic efficiency(ICE). Here, A novel SiO-MnO/Mn₂SiO₄-Mn_xSi anode material, prepared through scalable ball milling and heat treatment, is proposed for the first time, in which Mn₂SiO₄ and Mn_xSi alloy through solid-state reaction are embedded in the silicon oxide matrix to improve ICE. Half-cell testing shows that the ICE of pristine SiO increased from 52.5 % to 70.5 %, thanks to the solid-state reaction between SiO and MnO during the heat treatment, in which MnO consumed the SiO₂ generated during the disproportionation of SiO, thereby reducing the first irreversible loss of Li⁺ during the lithiation process. In addition, the Mn_xSi alloy phase can improve lithium-ion diffusion ability to a certain extent. This report provides a new approach to alleviate the ICE performance of SiO-based anode materials.