Core–shell-structured Mn2SnO4@Void@C as a stable anode material for lithium-ion batteries with long cycle life

Abstract

Owing to its high theoretical specific capacity, Mn₂SnO₄ has been regarded as a promising electrode material for lithium-ion batteries. However, in suffering from huge volume expansion and pulverization amidst the alloying/dealloying processes, it presents difficulties in applications as an anode material. Herein, a core–shell-structured Mn₂SnO₄@Void@C anode material was successfully synthesized using a layer-wise assembly and selective etching method. Tetraethyl silicate (TEOS) and resorcinol formaldehyde resin, serving, respectively, as sacrificial template (SiO₂) and carbon layer sources, were coated successively onto Mn₂SnO₄ particles. Adopting an alkali etching process, the SiO₂ template was removed, and a Mn₂SnO₄@Void@C was therewith constructed. As Mn₂SnO₄ is well wrapped by a carbon shell and there are enough voids therein, its volume expansion whilst cycling can be significantly buffered. Moreover, the porous structure in Mn₂SnO₄@Void@C can provide convenient channels for ion transport and alleviate volume changes. Mn₂SnO₄@Void@C exhibits upgraded capacity and long cycling stability, since its specific capacity is maintained at 783.1 mA h g⁻¹ at 100 mA g⁻¹ after 150 cycles and at 553.3 mA h g⁻¹ at 1000 mA g⁻¹ after 1000 cycles.