Curtailing the Overpotential of Li–CO<sub>2</sub> Batteries with Shape‐Controlled Cu<sub>2</sub>O as Cathode: Effect of Illuminating the Cathode
Anirudha Jena, He Chin Hsieh, Subashchandrabose Thoka, Shu‐Fen Hu, Ho Chang, Ru‐Shi Liu
Abstract
Abstract Li–air batteries are limited to lab‐scale research owing to the uninterrupted formation of discharge products. In the case of Li–CO 2 batteries, the increase in overpotential caused by Li 2 CO 3 formation results in cell death. In this study, Cu 2 O crystals having three different types of shapes (i.e., cubic, octahedral, and rhombic) were synthesized to compare their catalytic activity toward CO 2 reactions. The full‐cycle and long‐term stability test revealed that rhombohedral Cu 2 O facilitates Li 2 CO 3 decomposition more efficiently than that of cubic and octahedral Cu 2 O. The cycle was extended to investigate the photocatalytic activity of the rhombic Cu 2 O by illuminating the cell. The repeated cycles to 1 h showed a maximum overpotential of 1.5 V, which is 0.5 V lower than that of the cell without illumination. A postmortem analysis of the cell after dividing the cycles into segments demonstrated interesting results concerning the role of light and Cu 2 O during the cell cycle.