Dispersed MoS2 nanosheets in core shell Co3O4@C nanocubes for superior potassium ion storage

Potassium ion batteries (KIBs) are one of promising alternative candidates for next-generation energy storage systems because of their rich abundance and low cost, however, it still remains a great challenge to build optimum electrode materials for practical applications. This work unveils that a porous nanostructure consisted of ultra-fine MoS2 nanosheets embedded in hollow Co3O4 decorated carbon framework (Co3O4@C@MoS2) serves as the anode material for K+ storage. The metallic feature coupled with Co3O4 is beneficial for ionic/electronic transport and decreasing the interface resistance over Co3O4@C@MoS2. The hierarchical texture supplies sufficient interstitial space to accommodate the volume changes during the K+ electrodeposition/stripping, large specific area for electrode/electrolyte contact, and preferable electron structure for fast redox kinetics. A high capacity of 256 mAh g(-1) was displayed for the MoS2 based composite and a high capacity retention of 88.3% was maintained at a high rate of 500 mA g(-1) after 500 cycles. The superior K+ storage performance is ascribed to the favorable interface feature, rational structure design and the synergistic effect of individual composition. Our results shed new prospects for the optimized multi-interface construction of durable energy storage devices, and demonstrate the potential applications of MoS2 for superior K+ storage.