Electrospun Nanofibrous Aluminum Doped Antimony/Carbon as a Universal Anode Material for Lithium and Sodium‐Ion Batteries

Antimony-based anodes offer high theoretical capacities but face critical challenges such as severe volume expansion and poor cycle life in rechargeable batteries. Developing a suitable dopant for Sb-based anodes and integrating these materials with nanofiber architectures presents a promising pathway to address these limitations. This study investigates the effect of Al doping in Sb alloy-based nanofibers by comparing antimony nanofibers (Sb-NF) with aluminum-doped Sb-NF (Sb_0.95Al_0.05-NF). In lithium-ion batteries (LIBs), Sb-NF remains electrochemically active up to a 10 C-rate, while Sb_0.95Al_0.05-NF sustains cyclability even at 30 C-rate, delivering 73.9 mAh g^-1. For sodium-ion batteries (SIBs), both anodes function up to 25 C-rate, but Sb_0.95Al_0.05-NF achieves a reversible capacity of 117 mAh g^-1, significantly outperforming Sb-NF, which delivers 50 mAh g^-1. Long-term cycling studies on LIB show that Sb_0.95Al_0.05-NF retains nearly three times the capacity of Sb-NF after 300 cycles, with capacity retention of 14% and 9%, respectively. In SIBs, Sb_0.95Al_0.05-NF exhibits superior performance up to 200 cycles, however, both Sb-NF and Sb_0.95Al_0.05-NF electrodes are affected by electrolyte related degradation including sodium dendrite formation beyond 200 cycles. Cyclic voltammetry reveals higher diffusion coefficients for Sb_0.95Al_0.05-NF in both LIB and SIB configuration. These findings highlight the synergetic benefits of doping and nanofiber morphology in improving rate capability and cycling stability.