High-entropy NaCl-type metal chalcogenides as K-ion storage materials: role of the cocktail effect

Abstract

The drastic volume expansion of active materials and the shuttle effect of polychalcogenides hindered the development of anode materials for potassium-ion batteries (PIBs). Thus, various strategies have been used to overcome the negative effects associated with potassiation. Here, we propose a NaCl-type high-entropy metal chalcogenide (HEMC) prepared using a simple melting method as an anode material for PIBs. Unlike traditional high-entropy materials comprising inactive metals, NaCl-type HEMCs can realize the occupancy of cationic sites by active metals. We show that AgSnSbSe1.5Te1.5, a HEMC, produces short-range tiny cells during phase-change energy storage reactions, reconciling the participation of active and inactive metals to form various heterointerfaces and different functional metal nanoparticles. The kinetic and density functional theory analysis showed that the formation of heterointerfaces decreased the diffusion energy barrier of K+ and the inactive metal silver provided appropriate adsorption energy, suppressing the latent shuttle effect. The results show enhanced electrochemical performance owing to the elemental composition of high-entropy materials and the formation of tunable heterointerfaces and functional nanoparticles in electrochemical reactions, offering a new concept for the design of PIB anode materials.