Type-II heterojunction photocathode for CO 2 reduction and light-assisted metal–CO 2 batteries

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 12; no. 9; pp. 5133 - 5144
• Main Authors: Zhu, Yanbin, Wei, Yan, Li, Peize, Liu, Shujie, Zhang, Jiandong, Tian, Liyuan, Gao, Pengkun, Zhang, Yali, Li, Jie, Wang, Deyu, Shen, Yan, Wang, Mingkui
• Format: Journal Article
• Language: English
• Published: 27.02.2024
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/D3TA07450A

Light-assisted metal–CO 2 batteries have attracted extensive attention. It is highly desirable to develop a photocathodic catalyst to simultaneously facilitate the activation and transformation of CO 2 and maintain long-term operational stability. Here, for the first time we report a one-dimensional Fe 2 O 3 /Cu 2 O type-II heterojunction nanowire photocathode for light-assisted metal–CO 2 batteries. With this new photocathode, a Li–CO 2 battery can achieve an ultralow voltage gap of 0.19 V and a superior round-trip efficiency of 88% after 260 cycles under irradiation of full sunlight (AM 1.5 G). This cycling performance is the highest level ever reported (≤100 cycles) in the field of light-assisted metal–CO 2 batteries so far. The impressive performance can be attributed to the built-in electric field across the Fe 2 O 3 /Cu 2 O type-II heterojunction featuring desired catalytic capability for both CO 2 reduction/evolution kinetics and (photo)electrochemical reversibility. The Fe 2 O 3 /Cu 2 O type-II heterojunction photocathode also shows potential application in flexible energy storage devices.