In-situ preparation of Nb2O5 coated Si nanoparticles with pseudocapacitive effect for high-rate lithium ion batteries

Lithium-ion batteries with the merits of no memory effect, cycle stability, and proven technology have attracted greatly attention as an energy storage system in daily life. However, the anode of commercial lithium-ion batteries is layered graphite, delivering an unsatisfied capacity of 372 mAh g−1. In this work, Si nanoparticles were in-situ coated with Nb2O5 with core–shell structure via a simple hydrothermal method. The effect of the content of Nb2O5 shell on the Si core was investigated. As a result, [email protected]2O5 composite (SN-1) exhibits high capacity (2383 mAh g−1) and stable cycle life as anode materials for lithium-ion batteries. Even rate current improves to 5C, the SN-1 composite anode still delivers a high capacity (1221 mAh g−1). Such a superior electrochemical performance are attributed to the fact that Nb2O5 is evenly coated on the surface of the Si nanoparticles, acting as a stress buffer layer and surface stabilization layer, ensuring rapid ion diffusion. Meanwhile, Pseudocapacitance contribution is vital for enhanced lithium storage. Therefore, the cycling stability of the electrodes is further improved. These superior electrochemical properties make the method of in-situ coating Si particles hold promising potential for energy storage systems.