Superior Potassium Ion Storage via Vertical MoS2 “Nano‐Rose” with Expanded Interlayers on Graphene

Abstract Potassium has its unique advantages over lithium or sodium as a charge carrier in rechargeable batteries. However, progresses in K‐ion battery (KIB) chemistry have so far been hindered by lacking suitable electrode materials to host the relatively large K + ions compared to its Li + and Na + counterparts. Herein, molybdenum disulfide (MoS 2 ) “roses” grown on reduced graphene oxide sheets (MoS 2 @rGO) are synthesized via a two‐step solvothermal route. The as‐synthesized MoS 2 @rGO composite, with expanded interlayer spacing of MoS 2 , chemically bonded between MoS 2 and rGO, and a unique nano‐architecture, displays the one of the best electrochemical performances to date as an anode material for nonaqueous KIBs. More importantly, a combined K + storage mechanism of intercalation and conversion reaction is also revealed. The findings presented indicate the enormous potential of layered metal dichalcogenides as advanced electrode materials for high‐performance KIBs and also provide new insights and understanding of K + storage mechanism.