Interfacial regulation of aluminum-air batteries by biomass carbon quantum dots: Corrosion inhibition and electrochemical enhancement

Alkaline aluminum-air batteries (AABs) are promising candidates for next-generation energy storage technologies owing to their exceptional energy density, low cost, and inherent safety. However, their practical deployment is hindered by severe self-corrosion of the aluminum anode, leading to performance degradation and a shortened operational lifespan. Here, carbon quantum dots derived from Sophora japonica leaves (SCDs) are innovatively employed as electrolyte additives in alkaline AABs to improve anode corrosion resistance and achieve high-performance output. Corrosion evaluation reveals that 0.2 g L⁻¹ SCDs effectively modulate the interfacial stability of the anode, achieving a corrosion inhibition efficiency of 41.5%. Moreover, incorporating SCDs enables AABs to achieve a high anode utilization of 51.7%, with a specific capacity of 1538.5 mAh g⁻¹ and an energy density of 1800 Wh kg⁻¹, markedly surpassing the additive-free counterpart. A detailed mechanistic analysis indicates that SCDs form a stable, parallel-configured adsorption film on the Al surface, which modulates Al dissolution and enhances interfacial integrity, thereby facilitating more controlled battery reactions. This work offers new insights into the selection of AABs additives and reveals the interaction of carbon quantum dots with the Al surface on a molecular/atomic scale.