The Preparation of Porous CuO@F-GDY Nano-Arrays for High-Performance Sodium-Ion Battery Anodes.

The growing demand for energy storage systems makes it crucial to develop high-performance anode materials for sodium-ion batteries. This study proposes an innovative strategy for constructing a porous CuO@ fluorinated graphdiyne (F-GDY) composite anode guided by a F-GDY coating. The synergistic effect of Cu(OH)2 core contraction and F-GDY shell confinement led to the formation of a porous CuO structure while preserving the well-defined linear array morphology. The interfacial charge transfer between F-GDY and CuO modulates the electronic structure of CuO, significantly enhancing electron transport efficiency and sodium ion adsorption capacity. The porous structure effectively accommodates volume fluctuations during sodium-ion insertion/extraction, thereby facilitating the formation of a stable solid electrolyte interphase. Electrochemical tests demonstrate that the composite anode exhibits high reversible capacity (681 mAh g-1 after 100 cycles at 50 mA g-1) and excellent long-term cycling stability (maintaining 278 mAh g-1 after 1250 cycles at 2000 mA g-1). Mechanistic analysis further confirms that the sodium storage process is predominantly capacitive and possesses a high ionic diffusion coefficient. This study provides a new perspective for developing high-stability anode materials for SIBs that can accommodate volume changes.