Controlled Synthesis of SnO₂ Nanostructures as Alloy Anode via Restricted Potential Toward Building High‐Performance Dual‐Ion Batteries with Graphite Cathode

Abstract Dual‐ion batteries (DIBs) are considered one of the promising energy storage devices in which graphite serves as a bi‐functional electrode, i.e., anode and cathode in the aprotic organic solvents. Unlike conventional lithium‐ion batteries (LIBs), DIBs reversibly store the cations and anions in the anode and cathodes during redox reactions, respectively. The electrolyte is a source for both cations and anions, so the choice of electrolyte plays a vital role. In the present work, the synthesis of SnO₂ nanostructures is reported as a possible alternative for graphite anode, and the Li‐storage performance is optimized in half‐cell (Li/SnO₂) assembly with varying amounts of conductive additive (acetylene black) and limited working potential (1 V vs Li). Finally, a DIB using recovered graphite (RG) fabricated from spent LIB as a cathode and SnO₂ nanostructures as an anode under balanced loading conditions. Prior to the fabrication, both electrodes are pre‐cycled to eliminate irreversibility. An in‐situ impedance study has been employed to validate the passivation layer formation during the charge‐discharge process. The high‐performance SnO₂/RG‐based DIB delivered a maximum discharge capacity of 380 mAh g⁻¹. The electrochemical performance of DIB has been assessed by varying temperature conditions to evaluate their suitability in different climatic conditions.