Oxygen-bridged interfacial bonding over Sb2Se3-MXene heterostructures for promoting pseudocapacitive Na-ion storage

Antimony triselenide (Sb 2 Se 3 ) has been regarded as one promising electrode material for electrochemical Na-ion storage. However, the structural instability caused by irreversible volume expansion during cycling, poses a significant challenge for Sb 2 Se 3 -based electrodes. In this work, 1D/2D Sb 2 Se 3 /Ti 3 C 2 T x MXene heterostructures in the presence of the interfacial oxygen bridge (O-bridge) is rationally designed to enhance pseudocapacitive sodium-ion (Na + ) storage. Through experimental and theoretical validation, the integration of 1D Sb 2 Se 3 with O-terminated 2D Ti 3 C 2 T x MXene induces strong electronic coupling at the interface (Sb/Se-O-Ti) and significantly reduces the diffusion barrier of Na-ions along the preferred surface path, thereby stabilizing the sodiation/desodiation cycles and improving the durability and stability. It is revealed that the 1D/2D Sb 2 Se 3 /Ti 3 C 2 T x MXene heterostructured electrode exhibits a reversible capacity of nearly 600 mAh g −1 at 50 ​mA ​g −1 and maintains a stable capacity of around 220 mAh g −1 after 600 cycles. Theoretical calculations further elucidate the significant impact of O-bridge bonding on interfacial electron transfer and Na + adsorption behavior, highlighting the superior pseudocapacitive contribution and ion storage performance. This work provides new insights into the design of stable electrodes for sodium-ion batteries and offers a potential solution to address oxidation issues in 2D materials for electrochemical reactions.