Engineering Hollow Porous Carbon-Sphere-Confined MoS₂ with Expanded (002) Planes for Boosting Potassium-Ion Storage

Potassium-ion batteries (PIBs) are emerging as promising next-generation electrochemical storage systems for their abundant and low-cost potassium resource. The key point of applying PIBs is to exploit stable K-host materials to accommodate the large-sized potassium ion. In this work, a yolk–shell structured MoS2@hollow porous carbon-sphere composite (MoS2@HPCS) assembled by engineering HPCS-confined MoS2 with expanded (002) planes is proposed for boosting potassium-ion storage. When used as a PIB anode, the as-synthesized MoS2@HPCS composite shows superior potassium storage performance. It delivers a reversible capacity of 254.9 mAh g–1 at 0.5 A g–1 after 100 discharge/charge cycles and maintains 126.2 mAh g–1 at 1 A g–1 over 500 cycles. The superior potassium-ion storage performance is ascribed to the elaborate yolk–shell nanoarchitecture and the expanded interlayer of the MoS2 nanosheet, which could shorten the transport distance, enhance the electronic conductivity, relieve the volume variation, prevent the self-aggregation of MoS2, facilitate the electrolyte penetration, and boost the intercalation/deintercalation of K+. Moreover, the potential application of the MoS2@HPCS composite is also evaluated by assembled K-ion full cells with a perylenetetracarboxylic dianhydride cathode. Accordingly, the as-developed synthetic strategy can be extended to manufacture other host materials for PIBs and beyond.