B-site cation tuned perovskite oxide-carbon composites as dual-functional electrocatalysts for high-performance Li-O₂ batteries

Rechargeable lithium-oxygen (Li-O₂) batteries are of immense interest for zero-emission transportation driven by their exceptionally high theoretical energy density. A primary challenge is achieving a reversible oxygen reaction, which requires efficient bifunctional electrocatalysts to enhance reaction kinetics. This study investigated pristine perovskite (LaCoO₃, LaNiO₃, and LaMnO₃) nanoparticles, supported on a porous carbon matrix derived from spent paper cups. Combining experimental methods with density functional theory (DFT) calculations, the LaMnO₃/Carbon emerged as the superior electrocatalyst, a finding confirmed by rotating ring disk electrode (RRDE) analysis. Among various B-Site cation tuned perovskite oxide-carbon composites as an cathode catalyst in a laboratory Li-O₂ coin cell, the LaMnO₃/C achieved an exceptional discharge capacity of 6144 mAh g−1 at 100 mA g−1. The battery also demonstrated enhanced coulombic efficiency, cycling stability, and practical utility by powering a commercial 3 V blue light emitting diodes (LED) continuously for 48 h. The outstanding performance is attributed to LaMnO₃ unique properties, including its half-metallic electronic structure, strong Mn-O hybridization, and spin polarization, which ensure high conductivity and stability. Oxygen vacancies on LaMnO₃ act as catalytic centers for oxygen adsorption and reduction. Simultaneously, the conductive, waste-derived carbon framework also provides a substantial active interface that encourages oxygen uptake, thereby yielding superior dual electrocatalytic functionality for the oxygen reduction (ORR) and evolution (OER) reactions.