A flexible Li-CO2 batteries with enhanced cycling stability enabled by a IrO2/carbon fiber self-standing cathode

Abstract

Rechargeable Li-CO2 batteries provide a very promising approach to simultaneously solve energy shortage and the greenhouse effect. However, Li-CO2 batteries are facing several shortcomings, especially the slow CO2 oxidation and reduction kinetics, which deteriorate the energy efficiency and cycling life. Herein, IrO2/carbon fibers derived from kapok (IrO2/CK) are prepared via simple one-step carbonization and subsequent hydrothermal reaction. Benefitting from the favorable CO2 reduction and evolution catalytic activities of the loaded IrO2 nanoparticles, the enhanced electron transfer and reactants diffusion kinetics derived by the unique cross-linked hierarchical porous structure and the ample space for Li2CO3 deposition, the fabricated Li-CO2 battery, IrO2/CK as the cathode, shows ultra-long operation time more than 4000 h. More importantly, the cathode exhibits excellent mechanical flexibility conferred by the kapok, which can maintain the original structure during bending. The pouch-type flexible Li-CO2 battery with IrO2/CK cathode can steadily operate for 300 h under different bending conditions. This work will advance the development of flexible Li-CO2 batteries in the field of wearing energy storage devices.