Flat-Zigzag Interface Design of Chalcogenide Heterostructure toward Ultralow Volume Expansion for High-Performance Potassium Storage

Heterostructure construction of layered metal chalcogenides can boost their alkali-metal storage performance, where the charge transfer kinetics can be promoted by the built-in electric fields. However, these heterostructures usually undergo interface separation due to severe layer expansion, especially for large-size potassium accommodation, resulting in the deconstruction of heterostructures and battery performance fading. Herein, first a stable interface design strategy where two metal chalcogenides with totally different layer-morphologies are stacked to form large K+ transport channels, rendering ultralow interlayer expansion, is presented. As a proof of concept, the flat-zigzag MoS2/Bi2S3 heterostructures stacked with zigzag-morphology Bi2S3 and flat-morphology MoS2 present an ultralow expansion ratio (1.98%) versus MoS2 (9.66%) and Bi2S3 (9.61%), which deliver an ultrahigh potassium storage capacity of above 600 mAh g(-1) and capacity retention of 76% after 500 cycles, together with the built-in electric field of heterostructures. Once the heterostructures are used as an anode for potassium-based dual-ion batteries (K-DIBs), it achieves a superior full-cell capacity of approximate to 166 mAh g(-1) with a capacity retention of 71% after 400 cycles, which is an outstanding performance among the reported K-DIBs. This proposed interface stacking strategy may offer a new way toward stable heterostructure design for metal ions storage and transport applications.

Automated summary

The construction of heterostructures in layered metal chalcogenides can enhance their alkali-metal storage performance. A stable interface design strategy is proposed to stack two metal chalcogenides with different layer morphologies, which forms large potassium transport channels with low interlayer expansion. This design achieves high potassium storage capacity, capacity retention, and superior performance in potassium-based dual-ion batteries.