Zinc–air batteries offer high theoretical energy density, intrinsic safety, and abundant raw materials, making them attractive for large-scale energy storage and flexible electronics. However, their real-world deployment remains constrained by slow oxygen electrochemistry at the air electrode, which leads to high overpotentials, limited power density, and rapid performance degradation. Conventional bifunctional catalysts often suffer from poor active-site accessibility, particle agglomeration during synthesis, and inefficient charge transport, especially under prolonged operation. Recent efforts to couple electrocatalysis with external stimuli such as light have shown promise, but integrating photoactivity with durable, high-performance air electrodes remains challenging. Based on these challenges, it is necessary to carry out in-depth research on photo-enhanced electrocatalysts for zinc–air batteries.
Researchers from Donghua University and collaborating institutions report a light-enhanced zinc–air battery enabled by a novel photo-electroactive air cathode, published (DOI: 10.1016/j.esci.2025.100450) in eScience on January 2026. The study introduces a p–n heterojunction catalyst that combines graphitic carbon nitride with a carbon nanofiber network hosting dual cobalt active sites. Under light irradiation, the catalyst significantly accelerates oxygen reduction and evolution reactions, leading to higher power density, improved energy efficiency, and unprecedented cycling stability in both liquid and flexible zinc–air battery configurations.
The core innovation lies in the rational integration of photoactivity and electrocatalysis within a single air-electrode architecture. The catalyst consists of graphitic carbon nitride nanosheets coupled to a self-supporting carbon nanofiber framework embedded with two complementary cobalt active sites: cobalt nanoparticles encapsulated in carbon nanotubes and atomically dispersed Co–N₄ moieties. This design forms a type-II p–n heterojunction that promotes directional charge transfer when exposed to light.
Upon illumination, photogenerated electrons migrate toward the conductive carbon framework to drive the oxygen reduction reaction, while holes facilitate the oxygen evolution reaction on adjacent sites. This spatial separation suppresses charge recombination and lowers reaction energy barriers. Electrochemical measurements reveal a remarkably small oxygen reaction overpotential gap of 0.684 V under light, outperforming many state-of-the-art bifunctional catalysts.
When assembled into practical zinc–air batteries, the photo-enhanced system achieves a peak power density of 310 mW cm⁻² and maintains stable charge–discharge operation for over 1,100 hours. Flexible battery prototypes further demonstrate strong mechanical robustness, retaining performance under repeated bending. Density functional theory calculations confirm that the heterojunction modulates the electronic structure of cobalt sites, optimizing oxygen intermediate adsorption and reaction kinetics.
“This work demonstrates how light can be actively harnessed to reconfigure catalytic reaction pathways rather than simply serving as an external energy input,” said one of the study's senior authors. “By engineering a p–n heterojunction with dual cobalt sites, we were able to achieve both high activity and long-term durability in zinc–air batteries. The synergy between photogenerated charge carriers and electrochemical reactions opens new possibilities for designing next-generation air electrodes that operate more efficiently and under milder conditions.”
The findings provide a versatile strategy for advancing zinc–air batteries toward real-world applications, including grid-scale energy storage, wearable electronics, and solar-assisted power systems. By leveraging light to enhance oxygen electrochemistry, the approach reduces energy losses and extends device lifetime without relying on precious metals. Beyond zinc–air batteries, the design principles demonstrated here could be applied to other metal–air batteries and photo-assisted electrochemical systems. More broadly, this work highlights a promising pathway for integrating solar energy directly into electrochemical energy storage, potentially bridging the gap between renewable energy harvesting and efficient energy utilization.
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References
DOI
10.1016/j.esci.2025.100450
Original Source URL
https://doi.org/10.1016/j.esci.2025.100450
Funding information
This work is financially supported by the National Key Research and Development Program of China (2022YFE0138900), National Natural Science Foundation of China (21972017), the Fundamental Research Funds for the Central Universities (2232022D-18, CUSF-DH-T-2023061), Shanghai Sailing Program (22YF1400700) and the Chenguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission (22CGA37).
About eScience
eScience – a Diamond Open Access journal cooperated with KeAi and published online at ScienceDirect. eScience is founded by Nankai University (China) in 2021 and aims to publish high quality academic papers on the latest and finest scientific and technological research in interdisciplinary fields related to energy, electrochemistry, electronics, and environment. eScience provides insights, innovation and imagination for these fields by built consecutive discovery and invention. Now eScience has been indexed by SCIE, CAS, Scopus and DOAJ. Its impact factor is 36.6, which is ranked first in the field of electrochemistry.