Dynamic localized domains of metallic glasses enable high-capacity SbBi anodes for potassium-ion batteries

Abstract

Alloying with metallic glasses (MGs) is a promising strategy to overcome the challenges, including severe volume expansion, sluggish kinetics, and limited capacity, of anodes for potassium-ion batteries (PIBs). However, excessive MG will lead to low Coulombic efficiency and poor cycling stability. Here, we propose a model of deformation-induced dilatation to construct dynamic localized domains of MGs to control the amorphization degree. By selecting the dual-intermetallic Cu₂Sb@SbBi₂ heterojunctional composite as the anode for PIBs, the advantages of dynamic localized domains of MG are well demonstrated. At the interface between intercalation-type Cu₂Sb with small volume expansion and alloy-type SbBi₂ with large volume expansion, the two materials show distinct potassiation/depotassiation behaviours. This huge volume change leads to significant dilatation entanglement within the heterojunction. As a result, the dynamic localized domains of MG are generated owing to the deformation-induced volume expansion. Benefiting from this distinctive feature with dynamic localized domains of MG, the Cu₂Sb@SbBi₂ anode delivers a high reversible capacity of 672 mAh g⁻¹ and an initial Coulombic efficiency of 84.6%. This work demonstrates an engineering approach to regulate the amorphization of dynamic localized domains for achieving high-performance alloy anodes for PIBs.