An Electrochemical Study on the Impact of Charging Parameters on the Electrochemical Performance of Alloy‐Based C/Sn Composite Anodes for Sodium‐Ion Batteries

The electrochemical performance of C/Sn composite anodes (≈11 wt% carbon) for sodium‐ion batteries is systematically investigated under varying charging conditions. Galvanostatic cycling with potential limitation reveals a significant influence of charging protocols on capacity and stability. An optimized protocol, starting with a low current (74.4 mA g −1 ) followed by higher currents (372 mA g −1 ), achieves a first discharge capacity of 749 mAh g −1 , an initial Coulombic efficiency of 84.0%, and a stable capacity of 536 mAh g −1 after 100 cycles. A thorough investigation of charge/discharge profiles and incremental capacity analysis reveals a novel, current‐induced desodiation process at 0.2 V, enhancing cyclability. Asymmetric cycling reveals interdependence between sodiation and desodiation, with capacity fading linked to a reaction at 0.26 V. Cut‐off potential adjustments allows isolation of individual dealloying processes. The first process at 0.15 V remains stable under varying charging currents, while the second desodiation process (≈0.26 V) transforms from phase transition to solid solution. Long‐term cycling identifies potential indicators of performance degradation, which could be mitigated by modifying cycling parameters. An advanced understanding of the complex electrochemical mechanisms in the Na/Sn alloy system is essential for developing protocols to further improve high‐capacity anode materials for sodium‐ion batteries.