High-yield carbon nanofibers derived from nanoporous Cu catalyst alloyed with Ni for sodium storage with high cycling stability

• Ni alloying in nanoporous Cu catalyst shifts the d-band center, enhancing C2H2 adsorption and boosting CNF yield to 258.6%. • CNFs@Cu–Ni anode delivers high capacity (193.6 mAh·g−1 at 1.0 A·g−1) with excellent cycling stability over 1000 cycles. • Exceptional rate capability (158.9 mAh·g−1 at 5.0 A·g−1) in ether-based electrolyte, promising for fast-charging SIBs. • Full battery (CNFs@Cu–Ni//NVP) demonstrates practical viability, attributed to abundant Na+ adsorption sites.