A porous Zn cathode for Li–CO2 batteries generating fuel-gas CO

Abstract

Global climate change and energy concerns trigger worldwide interest in sustainable, economical CO₂ reductive transformation into valuable chemicals. However, traditional electro/thermo-catalysis strategies usually consume a large amount of energy and suffer from low efficiency. Herein, a three-dimensional porous fractal Zn cathode is synthesized by redox-coupled electrodeposition and it exhibits excellent electrocatalytic properties for CO₂-to-CO conversion. Inspired by the coupling of a metal battery and CO₂ electroreduction, a novel fuel-gas CO generating Li–CO₂ battery is firstly realized with the as-prepared porous fractal Zn cathode. Meanwhile, CO formation can be easily tuned within a wide range of discharge currents and reach a maximum faradaic efficiency of up to 67%. Finally, based on gas and solid discharge product analysis, the related mechanism of CO main product production is proposed as 2Li⁺ + 2CO₂ + 2e⁻ → CO + Li₂CO₃. Hence the present work presents a new way for the further development of metal–CO₂ batteries to generate useful chemicals and fuels besides electrical energy.