Bimetallic Sulfide Hollow Nanocubes Heterostructure Promotes Dual Coupling of Conversion and Alloying/Dealloying Reactions to Achieve Durable Potassium‐Ion Battery Anode

Conversion and alloying‐type transitional metal sulfides have attracted significant interests as anodes for Potassium‐ion batteries (PIBs) and Sodium‐ion batteries (SIBs) due to their high theoretical capacities and low cost. However, the poor conductivity, structural pulverization, and high‐volume expansions greatly limit the performance. Herein, Co1‐xS/ZnS hollow nanocube‐like heterostructure decorated on reduced graphene oxide (Co1‐xS/ZnS@rGO) composite is fabricated through convenient hydrothermal and post‐heat vulcanization techniques. This unique composite can provide a more stable conductive network and shorten the diffusion length of ions, which exhibits a remarkable initial charge capacity of 638.5 mA h g−1 at 0.1 A g−1 for SIBs and 606 mA h g−1 at 0.1 A g−1 for PIBs, respectively; It is worth noting that the composite presents remarkable long stable cycle performance in PIBs, which initially delivered 274 mA h g−1 and sustained the charge capacity up to 245 mA h g−1 at high current density of 1 A g−1 after 2000 cycles. A series of in situ/ex situ detections and first principle calculations further validate the high potassium ions adsorption ability of Co1‐xS/ZnS anode materials with high diffusion kinetics. This work will accelerate the fundamental construction of bimetallic sulfide hollow nanocubes heterostructure electrodes for energy storage applications. The as‐obtained bimetallic sulfides Co1‐xS/ZnS hollow nanocubes is fabricated through hydrothermal and post‐heat vulcanization processes. The optimized Co1‐xS/ZnS@rGO composite possesses hexagonal hollow cavity in the center of nanocubes which accommodates high‐volume expansion during the cycling process, resultantly obtained superior electrochemical performance. The Co1‐xS/ZnS@rGO heterostructure promotes dual coupling of alloying/dealloying and conversion reactions, therefore the K+ may highly insert/de‐insert in the electrode during the cycling process, resultantly improved the reversibility of anode materials.