Stress‐Electrochemical Coupled Reconstruction Engineering of CuSe ₂ into Cu ₂ Se Nanowire for Enhanced Sodium‐Ion Storage

Abstract The development of high‐performance electrode materials is typically constrained by capacity fading from irreversible structural evolution and restricted ion transport kinetics. To address these challenges, this study employs a synchronous stress‐electrochemical reconstruction strategy to construct 3D copper selenide nanowires with ultrafast sodium ion transport capabilities. Experimental and theoretical analyses elucidate the synchronous evolution mechanism of CuSe 2 transforming into Cu 2 Se nanowires under dual effects of pressure and electrochemical cycling. The synchronized growth of ultrahigh‐aspect‐ratio nanowires along the high‐energy (111) crystal plane (0.329 nm spacing) provides abundant active sites for rapid sodium‐ion insertion/extraction. Benefiting from the 3D networked architecture composed of ultrafine nanowires in monolithic electrodes, the composite effectively mitigates volume variations and selenide species loss. Consequently, the reconstruction electrode demonstrates exceptional rate capability (573.1 mAh g −1 at 0.2 A g −1 and 451.8 mAh g −1 at 50 A g −1 ) and outstanding cycling stability (581.9 mAh g −1 after 300 cycles at 0.2 A g −1 ). This in situ stress‐electrochemical reconstruction strategy overcomes the physical limitations of conventional synthesis‐assembly paradigms, achieving atomic‐level coupling between active materials and current collectors, while offering a novel paradigm for developing adaptive electrode systems.