Expanded MoS2@C nanosheets by three-roll milling for high-performance potassium ion batteries

Abstract

Molybdenum disulfide (MoS2) as a candidate material for potassium ion storage has attracted extensive attention. However, the slow reaction kinetics and nanosheet stacking during K+ intercalation result in poor rate performance and cycling performance. It is claimed that increasing the layer spacing and carbon coating are effective methods to improve these problems. So, MoS2@C nanosheets with large layer spacing (0.711 nm) are prepared by hydrothermal combined with three-roll milling. As the anode electrode for K+ storage, the MoS2@C nanosheet electrode remains a reversible discharge specific capacity of 164.5 mAh/g at 0.5 A/g after 300 cycles. Even at 2 A/g, it can still maintain 125.5 mAh/g at the 150th cycle. This study provides a new strategy for the preparation of large-spaced layered sulfide nanosheets and their application in rechargeable batteries.