Double transition-metal chalcogenide as a high-performance lithium-ion battery anode material

Transition-metal dichalcogenides (TMDs) are a recent addition to a growing list of anode materials for the next-generation lithium-ion battery (LIB). The actual performance of TMDs is however constrained by their limited electronic conductivity. For example, MoS₂, the most studied TMD, does not have adequate rate performance even in the few-layer form or after compounding with nitrogen-doped graphene (NG). WS₂, a TMD with a higher intrinsic electronic conductivity, is more suitable for high rate applications but its theoretical capacity is lower than that of MoS₂. Hence, we hypothesize that a composition-optimized composite of MoS₂, WS₂, and NG may provide high capacity concurrently with good rate performance. This is a report on the design and preparation of double transition-metal chalcogenide (MoS₂/WS₂)-nitrogen doped graphene composites where the complementarity of component functions may be maximized. For example the best sample in this study could deliver a high discharge capacity of 1195 mAh·g^-1 at 100 mA·g^-1 concurrently with good cycle stability (average of 0.02% capacity fade per cycle for 100 cycles) and high rate performance (only 23% capacity reduction with a 50 fold increase in current density from 100 mA·g^-1 to 5000 mA·g^-1).