Construction of heterojunctions for Mn-Sn bimetallic sulfides @N-doped carbon nanorods as high-performance anode for lithium-ion batteries

Abstract

MnS is considered as a potential anode own to its merits of high specific capacity, suitable voltage potential, and unique α→β phase transition reaction. Nevertheless, its intrinsic low conductivity, volume variation, and polysulfide dissolution during the lithiation/delithiation process, resulting in inferior cycling performance, then limit its practical application for LIBs. Herein, a novel anode material composited of Mn-Sn bimetallic sulfides heterostructure and N-doped carbon shell (MnS/SnS@NC) is designed. In such a designed MnS/SnS@NC composite, the N-doped carbon is tightly wrapped in the inner MnS/SnS heterostructure through the C-S-Mn bond, which is beneficial to keep the structural stability and enhance the electrochemical reaction kinetics during the lithiation/delithiation process. Furthermore, the heterostructure boosts the ion and electron transfer, and the N-doped carbon buffers the volume change during the cycling process. As a result, the MnS/SnS@NC delivers an excellent long-cycle performance (719.6 mAh g−1 at 1.0 A g−1 after 1000 cycles) and an outstanding rate performance (416.6 mAh g−1 at 5 A g−1).