Core–shell structured MnSiO3 supported with CNTs as a high capacity anode for lithium-ion batteries

Abstract

Metal silicates are good candidates for use in lithium ion batteries (LIBs), however, their electrochemical performance is hindered by their poor electrical conductivity and volume expansion during Li⁺ insertion/desertion. In this work, one-dimensional core–shell structured MnSiO₃ supported with carbon nanotubes (CNTs) (referred to as CNT@MnSiO₃) with good conductivity and electrochemical performance has been successfully synthesized using a solvothermal process under moderate conditions. In contrast to traditional composites of CNTs and nanoparticles, the CNT@MnSiO₃ composite in this work is made up of CNTs with a layer of MnSiO₃ on the surface. The one-dimensional CNT@MnSiO₃ nanotubes provide a useful channel for transferring Li⁺ ions during the discharge/charge process, which accelerates the Li⁺ diffusion speed. The CNTs inside the structure not only enhance the conductivity of the composite, but also prevent volume expansion. A high reversible capacity (920 mA h g⁻¹ at 500 mA g⁻¹ over 650 cycles) and good rate performance were obtained for CNT@MnSiO₃, showing that this strategy of synthesizing coaxial CNT@MnSiO₃ nanotubes offers a promising method for preparing other silicates for LIBs or other applications.