High-Efficiency and Stable Li-CO 2 Battery Enabled by Carbon Nanotube/Carbon Nitride Heterostructured Photocathode

• Published in: Angewandte Chemie International Edition 2022-01, Vol.61 (4), p.e202114612
• Main Authors: Li, Jiaxin, Zhang, Kun, Zhao, Yang, Wang, Chuang, Wang, Lipeng, Wang, Lie, Liao, Meng, Ye, Lei, Zhang, Ye, Gao, Yue, Wang, Bingjie, Peng, Huisheng
• Format: Article
• Language: English
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202114612

Li-CO batteries are explored as promising power systems to alleviate environmental issues and to implement space applications. However, sluggish cathode kinetics of CO reduction/evolution result in low round-trip efficiency and poor cycling stability of the fabricated energy-storage devices. Herein, we design a heterostructued photocathode comprising carbon nanotube and carbon nitride to accelerate cathode reactions of a Li-CO battery under illumination. Benefiting from the unique defective structure of carbon nitride and favorable interfacial charge transfer, the photocathode effectively harvests ultraviolet-visible light to generate abundant photoexcited carriers and coordinates energetic photoelectrons/holes to participate in the discharge/charge reactions, leading to efficient photo-energy utilization in decreasing reaction barriers and enhancing thermodynamic reversibility of Li-CO battery. The resulting battery delivers a high round-trip efficiency of 98.8 % (ultralow voltage hysteresis of 0.04 V) and superior cycling stability (86.1 % efficiency retention after 100 cycles).