Double\nTransition-Metal Chalcogenide as a High-Performance\nLithium-Ion Battery Anode Material

Abstract

Transition-metal\ndichalcogenides (TMDs) are a recent addition to\na growing list of anode materials for the next-generation lithium-ion\nbattery (LIB). The actual performance of TMDs is however constrained\nby their limited electronic conductivity. For example, MoS₂, the most studied TMD, does not have adequate rate performance even\nin the few-layer form or after compounding with nitrogen-doped graphene\n(NG). WS₂, a TMD with a higher intrinsic electronic conductivity,\nis more suitable for high rate applications but its theoretical capacity\nis lower than that of MoS₂. Hence, we hypothesize that\na composition-optimized composite of MoS₂, WS₂, and NG may provide high capacity concurrently with good rate performance.\nThis is a report on the design and preparation of double transition-metal\nchalcogenide (MoS₂/WS₂)-nitrogen doped graphene\ncomposites where the complementarity of component functions may be\nmaximized. For example the best sample in this study could deliver\na high discharge capacity of 1195 mAh·g^–1 at\n100 mA·g^–1 concurrently with good cycle stability\n(average of 0.02% capacity fade per cycle for 100 cycles) and high\nrate performance (only 23% capacity reduction with a 50 fold increase\nin current density from 100 mA·g^–1 to 5000\nmA·g^–1).