The structure control of ZnS/graphene composites and their excellent properties for lithium-ion batteries

Abstract

ZnS/graphene composites are prepared using a facile solvothermal process by combining the reduction of graphene oxide with the growth of ZnS aggregates in one step. ZnS aggregates with diameters of 50–90 nm assembled from ZnS nanocrystals are homogeneously anchored on graphene sheets as spacers to keep the neighboring sheets separated. As anode materials for lithium-ion batteries, the ZnS/graphene composite electrode exhibits discharge and charge capacities of 1464 and 1010 mA h g⁻¹ for the initial cycle at 100 mA g⁻¹, and shows excellent cyclability with a capacity of 570 mA h g⁻¹ after 200 cycles at a current density of 200 mA g⁻¹. The total specific capacity of ZnS/graphene composites is higher than the sum of pure graphene and ZnS, highlighting the importance of aggregates of ZnS and the anchoring structure of aggregates on graphene sheets for maximum utilization of active ZnS aggregates and graphene for energy storage applications in high-property lithium-ion batteries.