Bio-inspired design of strong self-standing cathode toward highly stable reversible Li-CO2 batteries

Abstract

Abstract The hysteresis kinetics of carbon dioxide reduction reaction (CDRR) and evolution reaction (CDER) reaction are major barriers toward the practical implementation of lithium-carbon dioxide (Li-CO2) batteries. Herein, a free-standing and binder-free cathode composed of rutile TiO2 nanorod arrays (TiO2 NAs) and carbonized natural sponge was designed and realized by a simple seeds-assisted construction. The novel air cathode was found to exhibits a high specific capacity of 4.38 mAh cm−2 and long cycle life of more than 1600\xa0h, as well as the discharge products, which would deposit at the surface of the TiO2 NAs rather than carbon substrate during the discharge process. The improved performance can be ascribed to the interconnected conductive sponge framework with macropore and mesoporous channels that can house more discharge products, and the reactant molecules can unrestricted contact with the active sites. Furthermore, the good adhesion to the carbon substrate and the numerous available catalytic sites of the TiO2 NAs contribute intimate contact of the discharge products with the TiO2 NAs, improving CDRR and CDER kinetics effectively and boosting the electrochemical reactions. This TiO2/Sponge represents a promising design in the development of a nature-inspired, self-standing, and binder-free electrode for high-performance Li-CO2 batteries.