Mo-doped SnO2 mesoporous hollow structured spheres as anode materials for high-performance lithium ion batteries

Abstract

We designed a facile infiltration route to synthesize mesoporous hollow structured Mo doped SnO₂ using silica spheres as templates. It is observed that Mo is uniformly incorporated into SnO₂ lattice in the form of Mo⁶⁺. The as-prepared mesoporous Mo-doped SnO₂ LIBs anodes exhibit a significantly improved electrochemical performance with good cycling stability, high specific capacity and high rate capability. The mesoporous hollow Mo-doped SnO₂ sample with 14 at% Mo doping content displays a specific capacity of 801 mA h g⁻¹ after 60 cycles at a current density of 100 mA g⁻¹, about 1.66 times higher than that of the pure SnO₂ hollow sample. In addition, even if the current density is as high as 1600 mA g⁻¹ after 60 cycles, it could still retain a stable specific capacity of 530 mA h g⁻¹, exhibiting an extraordinary rate capability. The greatly improved electrochemical performance of the Mo-doped mesoporous hollow SnO₂ sample could be attributed to the following factors. The large surface area and hollow structure can significantly enhance structural integrity by acting as mechanical buffer, effectively alleviating the volume changes generated during the lithiation/delithiation process. The incorporation of Mo into the lattice of SnO₂ improves charge transfer kinetics and results in a faster Li⁺ diffusion rate during the charge–discharge process.