Ultrafine RuO2 nanoparticles/MWCNTs cathodes for rechargeable Na-CO2 batteries with accelerated kinetics of Na2CO3 decomposition

• Published in: 中国化学快报（英文版） 2023, Vol.34 (3), p.531-535
• Main Authors: Zhenzhen Wang, Yichao Cai, Youxuan Ni, Yong Lu, Liu Lin, Haoxiang Sun, Haixia Li, Zhenhua Yan, Qing Zhao, Jun Chen
• Format: Article
• Language: English
• ISSN: 1001-8417

Na-CO2 batteries have attracted extensive attention due to their high theoretical energy density(1125 Wh/kg),efficient utilization of CO2,and abundant sodium resources.However,they are trapped by the sluggish decomposition kinetic of discharge products(mainly Na2CO3)on cathode side during the charging process.Here we prepared a series of nano-composites composed of RuO2 nanoparticles in situ loaded on activated multi-walled carbon nanotubes(RuO2@a-MWCNTs)through hydrolyzing reaction followed by calcination method and used them as cathode catalysts to accelerate the decomposition of Na2CO3.Among all catalysts,the RuO2@a-MWCNTs with appropriate ratio of RuO2(49.7 wt％)demon-strated best stability and rate performance in Na-CO2 batteries,benefiting from both high specific surface area(160.3 m2/g)and highly dispersed Ru02 with ultrafine nanostructures(～2nm).At a limited capacity of 500 mAh/g,Na-CO2 batteries could afford the operation of over 120 cycles at 100mA/g,and even at the current density to 500mA/g,the charge voltage was still lower than 4.0 V after 40 cycles.Further theoretical calculations proved that RuO2 was the catalytically active center and contributed to the de-composition of Na2CO3 by weakening the C=O bond.The synergetic functions of high specific surface(CNTs)and high catalytic activity(RuO2)will inspire more progress on metal-CO2 batteries.