Single-metal site-embedded conjugated macrocyclic hybrid catalysts enable boosted CO2 reduction and evolution kinetics in Li-CO2 batteries

• Published in: Cell reports physical science Vol. 2; no. 10; p. 100583
• Main Authors: Wang, Jian-Hui, Zhang, Yu, Liu, Ming, Gao, Guang-Kuo, Ji, Wenxin, Jiang, Cheng, Huang, Xin, Chen, Yifa, Li, Shun-Li, Lan, Ya-Qian
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 20.10.2021
• Subjects: CNTs; CO2 reduction; conjugated macrocyclic; Li-CO2 battery; single-metal sites; single-metal sites; conjugated macrocyclic; Li-CO2 battery; CNTs; CO2 reduction
• ISSN: 2666-3864; 2666-3864
• DOI: 10.1016/j.xcrp.2021.100583

Rechargeable Li-CO2 batteries, an emerging battery technology to confront the environmental and energy crises, hold promise for CO2 fixation and energy storage. However, state-of-the-art Li-CO2 systems generally suffer from sluggish CO2 reduction/evolution reaction kinetics, and powerful catalysts that can simultaneously facilitate both processes are much desired but largely unrealized. Here, we report a series of Ru, metal-chelated conjugated N4-macrocyclic metal complex (M-CPY) and carbon nanotube (CNT)-based hybrid materials (Ru/M-CPY@CNT) with the advantages of highly dispersed Ru and M-CPY, high-conductivity, and tunable loadings that can be applied as multi-functional cathode catalysts. Ru/Co-CPY@CNT-2-based cells deliver an ultra-low overpotential (0.84 V) and enable fully reversible discharge/charge with a high specific capacity of 24,740 mAh/g within 2.0–4.5 V at 200 mA/g. It can rapidly discharge/charge for 180 cycles at 500 mA/g, and the CO2 activation process is intensively investigated by density functional theory (DFT) calculations. [Display omitted] •Ru/M-CPY@CNT with multi-functionality is prepared via a self-assembly method•Ru/Co-CPY@CNT can be applied as efficient cathode catalyst in Li-CO2 batteries•Ru and Co-CPY show synergistic effect for the discharge/charge process•The CO2 activation ability of Co-CPY is revealed by DFT calculations Wang et al. report a series of Ru/M-CPY@CNT hybrid materials assembled from single-metal site-embedded conjugated macrocyclic compounds, Ru nanoparticles, and CNTs. The obtained hybrid materials enable enhanced CO2 reduction and evolution kinetics in Li-CO2 batteries.