Application Of Transition Metal Sulfides And Their Composite Materials In Lithium Ion Battery Anodes

Transition metal sulfides?TMS?are considered to have great potential as anode materials for lithium-ion batteries due to their unique properties and high theoretical specific capacity.However,their intrinsic limitations have restricted their application.To solve this problem,it is common and useful to composite transition metal sulfide with graphene.In this paper,3D MoS₂/RGO composites were prepared by a simple one-pot stepwise hydrothermal method;and a series of mixed metal sulfide composites of CoS₂,MoS₂ and reduced graphene oxide were prepared with rational synthesis strategy.The obtained composite materials performed well in lithium storage and the details are as follows:1)The 3D MoS₂/RGO composite with three-dimensional structure was synthesized by a facile one-pot stepwise hydrothermal method.A three dimensional graphene oxide matrix can be obtained after the first hydrothermal treatment and in the second step of hydrothermal treatment,MoS₂ nanoflower subunits formed and anchored on the previously formed three-dimensional graphene matrix.As-synthesized 3D MoS₂/RGO composites exhibited improved lithium storage properties.2)A series of CoS₂/MoS₂/RGO composites were prepared with a rational hydrothermal synthesis strategy.In this process,Co²⁺not only acted as nucleation centers,but also helped to compromise charge incompatibility between MoO₄^2-and graphene oxide.Besides,layered MoS₂ also reduced the aggregation of CoS₂ nanoparticles.Among these mixed metal sulfides composites,CoS₂/MoS₂/RGO-1:1 composite electrode exhibited best cycle performance and also performed better than the corresponding single metal sulfide composites.Meanwhile,CoS₂/MoS₂/RGO-1:1 composite electrode also exhibited well in rate performance.