Dual‐Functional Carbon Dots as Electrolyte Additives for Enhancing Cathode Catalysis and Anode Stability in Li–O ₂ Batteries

ABSTRACT

Li–O ₂ batteries garner widespread attention owing to their remarkable theoretical specific capacity. Nevertheless, the feasible implementation of the system is hindered by sluggish cathode reaction kinetics and poor anode stability. Herein, the carbon dots (CDs) with ‐OH, ‐NH ₂ , and ‐COOH groups are synthesized and employed as electrolyte additives for Li–O ₂ batteries. The CDs are well‐dispersed in the electrolyte which promotes the formation of Li ₂ O ₂ through hydrogen bond‐mediated dissolution, whereas their high catalytic activity simultaneously facilitates Li ₂ O ₂ decomposition, thereby enhancing cathode reaction kinetics. Additionally, CDs can suppress dendrite growth on the Li anode and reduce dead Li accumulation by improving the properties of the electrolyte, including ionic conductivity, raising the Li ⁺ transference number, ensuring strong electronic insulation, and altering the Li ⁺ solvation structure. Therefore, the introduction of CDs enables the Li–O ₂ battery to achieve a discharge capacity of 5422.2 mAh g ⁻¹ and maintain stable cycling performance of 700 h at 100 mA g ⁻¹ . This work underscores the remarkable efficacy of CDs electrolyte additive in enhancing the performance of the Li–O ₂ battery, providing a new direction for addressing existing challenges of the battery.