Electron structure and reaction pathway regulation on porous cobalt-doped CeO2/graphene aerogel: A free-standing cathode for flexible and advanced Li-CO2 batteries

Abstract

Li-CO2 batteries present considerable prospects both in resourcing CO2 and remedying the unsatisfied performance of current energy storage devices. Herein, a porous self-supporting cathode for Li-CO2 battery is fabricated through straightforward anchoring of two-dimensional (2D) cobalt-doped CeO2 nanosheets on graphene aerogel, bypassing the addition of binder and the complicated manufacturing process. The combination of CeO2 and Co3O4 results in the reorganization of electronic structure by strongly coupled nanointerfaces, enhancing the reversible formation and decomposition of Li2CO3. Meanwhile, the unique porous structure facilitates the diffusion of CO2 and electrolyte in Li-CO2 batteries. The as-assembled Li-CO2 battery achieves a superior discharge capacity (7860 mAh/g) and competitive cycling stability (>100 cycles). In particular, a flexible Li-CO2 battery is developed with the freestanding cathode, which can provide a stable power output during multi-angle bending and folding. The improved conductivity, CO2 adsorption ability and the electrochemical reaction pathway are revealed by density functional theory (DFT) calculations in detail. This work sheds new light on the development of advanced and flexible Li-CO2 batteries for wearable electronics.