Light-Driven Photocathodes in Li/Zn-O2 (air) Batteries: An Analytical Review, Technological Breakthroughs and Future Challenges

Abstract

The rapid advancement of renewable energy technologies has intensified the demand for high-performance energy storage systems. Metal-O2 (air) batteries, specifically Li-O2 (air) and Zn-O2 (air) variants, present exceptional theoretical energy densities, positioning them as promising candidates for next-generation storage solutions. However, significant challenges remain in optimizing the oxygen reduction and evolution reactions (ORR/OER), critical for achieving high efficiency and stability. Recent developments in light-assisted metal-O2 (air) battery designs leverage photonic energy to enhance oxygen reduction and evolution reactions, offering reduced charge voltages, improved round-trip efficiencies, and extended lifetimes. This review critically evaluates the breakthroughs and limitations in photo-assisted Li/Zn-O2 (air) battery technologies, with a focus on novel photocathode materials, including advanced semiconductors, heterojunction configurations, and nanostructured catalysts. We systematically highlight the key properties of these photocathode materials, evaluating their photon-utilization efficiency, charge separation capabilities, recombination rates, charging/discharging profiles, efficient decomposition of discharge products and stability under operational conditions. Emphasis is placed on advanced strategies to enhance light absorption, aiming to optimize photocatalytic efficiency, electronic properties, and catalytic stability, thereby overcoming current performance barriers. By providing a comprehensive analysis of the current landscape and emerging trends, this review aims to chart a path forward for the development of more robust, efficient, and sustainable light-assisted Li/Zn-O2 (air) batteries, highlighting the essential role of innovative photocathode materials in achieving next-generation energy storage solutions.