CoFe2O4 Nanoparticles on Bio-Based Polymer Derived Nitrogen Doped Carbon as Bifunctional Electrocatalyst for Li-Air Battery

Lithium-air batteries (LABs) are gaining attention as a promising energy storage solution. Their theoretical energy density of 3,505 Whkg⁻¹ exceeds that of conventional lithium-ion batteries (500–800 Whkg⁻¹). The commercial viability and widespread adoption of lithium-air batteries face challenges such as poor cycling stability, limited lifespan, and unresolved side reactions. In this study, we synthesized spinel CoFe₂O₄-decorated on bio-based poly(2,5-benzimidazole) derived N-doped carbon for electrocatalysts. Notably, strong metal-substrate interaction (SMSI) was observed through various characterizations. The bifunctional electrocatalytic activity and stability toward oxygen reduction reaction and oxygen evolution reaction were significantly enhanced by the SMSI, The LAB demonstrated a high discharge capacity of 18,356 mAhg⁻¹ at a current density of 200 mAg⁻¹, maintaining a remarkable discharge capacity of 1,000 mAhg⁻¹ even at a high current density of 400 mAg⁻¹ for 200 cycles. CoFe₂O₄-decorated on bio-derived ABPBI holds promise as a practical air-breathing electrode for high-capacity rechargeable LABs.