High‐Efficiency and Stable Li−CO<sub>2</sub> Battery Enabled by Carbon Nanotube/Carbon Nitride Heterostructured Photocathode
Jiaxin Li, Kun Zhang, Yang Zhao, Chuang Wang, Lipeng Wang, Lie Wang, Meng Liao, Lei Ye, Ye Zhang, Yue Gao, Bingjie Wang, Huisheng Peng
Abstract
Abstract Li−CO 2 batteries are explored as promising power systems to alleviate environmental issues and to implement space applications. However, sluggish cathode kinetics of CO 2 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 2 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 2 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).