An urchin-like Bi/Bi2S3 active heterostructure anode toward high electrochemical performance potassium-ion batteries

Although the Bi ₂S ₃ material is one of the most promising anodes for potassium-ion batteries, its practical application has been hindered by low electronic conductivity, side reactions, and huge volume changes. In this work, a novel carbon-coated Urchin-like Bi/Bi ₂S ₃ active heterostructure anode (denoted as Urchin-like Bi/Bi ₂S ₃@C) is designed to promote the cycling stability as well as rate properties, ultimately realizing high electrochemical performance potassium-ion batteries. Specifically, the as-designed Urchin-like structure is used to mitigate the volume change of the anisotropy of the components during cycling process, and the unique Bi/Bi ₂S ₃ active heterostructure is applied to enhance the intrinsic electronic conductivity and maintain the high capacity. In addition, the carbon coating layer not only ensures the stability of such Urchin-like structure but also inhibits the agglomeration of alloy particles. As a result, the Urchin-like Bi/Bi ₂S ₃@C anode can provide a high discharge capacity of 388 mAh g ⁻¹ even after 340 cycles at a high current density of 2.0 A g ⁻¹, and its rate properties are also improved significantly. This study provides a new strategy for achievement the efficient potassium storage performance of Bi ₂S ₃ anode, and systematically explains its advanced nature and modification mechanism.