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, CoS/ZnS hollow nanocube-like heterostructure decorated on reduced graphene oxide (CoS/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 at 0.1 A g for SIBs and 606 mA h g at 0.1 A g 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 and sustained the charge capacity up to 245 mA h g at high current density of 1 A g after 2000 cycles. A series of in situ/ex situ detections and first principle calculations further validate the high potassium ions adsorption ability of CoS/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.