Rational construction of Sb2Se3 wrapped bimetallic selenide as anode material toward efficient sodium storage performance

Antimony selenide (Sb2Se3) is considered an ideal anode material candidate for sodium-ion batteries (SIBs) due to its abundant resources, low bandgap, and high theoretical capacity. However, the big volume changes, poor structural stability, and slow dynamics have led to rapid capacity decay and severely limited its application in large-scale energy storage. To resolve these problems, we designed a rod-shaped Sb2Se3 composite material coated with Co and Sb bimetallic selenides using a one-pot hydrothermal method (CoSb2Se4@Sb2Se3) to activate the redox reaction of SIBs anode. The presence of a suitable Co content coating layer (2CSS) enables Sb2Se3 to adapt to volume expansion during cycling, thereby improving structural and cycling stability. After 160 cycles under 1 A g−1 conditions, the capacity retention rate is 81.4%. 2CSS also exhibits rapid ion diffusion ability and efficient Na+ storage capacity, which is beneficial for improving rate performance. Even at 10 A g−1, it can provide a reversible discharge capacity of 222.2 mAh g−1. A series of electrochemical performance tests strongly demonstrate that coatings can better utilize the capacity advantage of alloy electrodes to improve electrochemical performance. This work provides an effective strategy for constructing high-performance cathode materials for SIBs.