ZnAl-layered double hydroxides template-induced formation of ZnO/ZnSe heterostructures on the surface of coal-tar-pitch-derived carbon for high-efficiency sodium storage

Abstract Developing high-performance anodes from low-cost industrial byproducts is crucial for advancing sodium-ion batteries. Herein, we report a zinc–aluminum layered double hydroxide (ZnAl-LDH) template-induced strategy for fabricating ZnO/ZnSe heterojunctions embedded within hierarchical porous carbon derived from coal tar pitch. The LDH serves as a dual functional structural template and pore-forming agent, enabling the in situ construction of intimately coupled ZnO/ZnSe–C interfaces. The designed ZnO/ZnSe heterostructure offers notable advantages: the heterojunction boosts charge transfer via interfacial contact between the two active components, while the mixed O2−/Se2− anion environment, combined with nanodispersed ZnO/ZnSe and the conductive carbon matrix, effectively enhances the reaction kinetics and mitigates volume strain. Consequently, the composite anode delivers a high reversible capacity of 637.5 mAh g−1 at 100 mA g−1 and retains 259.7 mAh g−1 after 1000 cycles at 5 A g−1. Kinetic analysis indicates that the superior rate performance is attributed to a dominant capacitive contribution (93.3% at 1.2 mV s−1). A full cell configured with an Na3V2(PO4)3 cathode demonstrates practical viability, retaining 147.5 mAh g−1 after 100 cycles. This work highlights the effectiveness of LDH-templated synthesis in constructing advanced heterostructure anodes for efficient sodium storage.