A diatom frustule-based Mn2SiO4@C@SiO2 multilayer-structure composite as a high-performance anode electrode material for lithium-ion batteries†

Owing to its abundant reserves and high theoretical specific capacity, silica has been tested as an anode material for lithium-ion batteries. However, its utilization is limited by volume expansion during cycling and low electrical conductivity. Most studies have focused on designing nanostructures of SiO₂ or combining them with conductive phases to solve this problem. In this work, diatom-based biological silica with a natural hollow porous structure was used as a template to prepare diatom-based silica anode materials coated with Mn₂SiO₄ nanoclusters via a hydrothermal method. A composite material with a structure of Mn₂SiO₄@C@SiO₂ was obtained. The Mn/SiO₂@C@SiO₂ sandwich structure derived during electrochemical reduction has a high capacity and excellent rate performance and significantly inhibits the volume expansion of SiO₂. The prepared anode material (AFD@C-Mn-40) with the Mn/SiO₂@C@SiO₂ structure retained a specific discharge capacity of approximately 1112 mA h g⁻¹ after 100 cycles at 100 mA g⁻¹, which provides new prospects for the large-scale application of silica.