Study On Tin Oxide As Cathode Catalyst For Lithium-air Batteries

As a kind of novel energy conversion device,lithium-air（Li-air）batteries have attracted great attention in recent years.However,the unclear mechanism,the lack of efficient cathode catalysts and the formation of lithium dendrite prevent their commercial applications.In this work,the catalysts of SnO₂,SnO₂@C and SnO₂@RGO were successfully synthesized,their abilities to improve the discharge capacity,cycling performance and rate capability of Li-air batteries were comparatively investigated.The Li-air battery with SnO₂ as the cathode catalyst exhibited lower overpotential,larger discharge capacity,higher rate-capability and better cycling performance than the battery with only Super cathode.This could be attributed to the large pore size in the SnO₂ synthesized by hydrothermal synthesis,which is beneficial to the storage of the cathode products and the diffusion of oxygen.In order to improve the catalytic performance of SnO₂ catalyst,SnO₂@C nanomicrospheres were synthesized by hydrothermal synthesis.The Li-air battery with SnO₂@C as cathode catalyst demostrated lower overpotential,higher discharge capacity and better cycling performance than the battery with SnO₂ catalyst.The enhancement could be attributed to the larger specific surface area to exposing more catalytic active sites.To further enhance the catalytic performance of SnO₂ as cathode catalyst of Li-air batteries,an RGO supported catalyst,SnO₂@RGO,was synthesized because of the advantages of large specific surface area,good electronic conductivity and great malleability.The Li-air batteries with SnO₂@RGO as the cathode catalyst displayed higher discharge capacity and better rate-capability.