Promoting the Electrocatalytic Activity of Ti3C2Tx MXene by Modulating CO2 Adsorption through Oxygen Vacancies for High-Performance Lithium-Carbon Dioxide Batteries

Graphical Oxygen vacancy-enriched TiO 2 nanoparticles grown in situ on Ti 3 C 2 T x MXene enhance CO 2 adsorption and Li 2 CO 3 decomposition, thereby remarkably facilitating CO 2 involved electrode reactions for overall Li-CO 2 batteries. Lithium-carbon dioxide (Li-CO 2 ) batteries are considered as a most auspicious energy storage systems owing to their high capacity and the ability of capturing CO 2 . However, there are still some critical issues needed to be addressed before their practical application, such as high charge potential and poor cyclability. Herein, oxygen vacancy-enriched TiO 2 nanoparticles grown in situ on Ti 3 C 2 T x MXene (O V -TiO 2 /MXene) are synthesized as catalysts for Li-CO 2 batteries by facile one-step ethanol heat treatment of the MXene nanosheets. The thermodynamically metastable Ti atom on the surface of MXenes serves as nucleating sites, which play a critical role in generating the relatively stable vacancy-rich TiO 2 nanoparticles. The spontaneously generated oxygen vacancies can enhance CO 2 adsorption, which is beneficial to CO 2 involved electrode reactions. The Li-CO 2 batteries with O V -TiO 2 /MXene electrodes deliver noteworthily reduced charge voltage of 3.37 V at 100 mA g −1 , and a superb cycling performance of 158 cycles. This work highlights the significant role of oxygen vacancies in activating CO 2 in Li-CO 2 batteries, instrumental to the development of high-performance electrocatalysts for Li-CO 2 batteries and beyond.