A phenazine-based high-capacity and high-stability electrochemical CO₂ capture cell with coupled electricity storage

Carbon dioxide capture technologies will be important for counteracting difficult-to-abate greenhouse gas emissions if humanity is to limit global warming to acceptable levels. Electrochemically mediated CO2 capture has emerged as a promising alternative to conventional amine scrubbing, offering a potentially cost effective, environmentally friendly and energy efficient approach. Here we report an electrochemical cell for CO2 capture based on pH swing cycles driven through proton-coupled electron transfer of a developed phenazine derivative, 2,2'-(phenazine-1,8-diyl)bis(ethane-1-sulfonate) (1,8-ESP), with high aqueous solubility (>1.35 M) over pH range 0.00-14.90. The system operates with a high capture capacity of 0.86-1.41 mol l(-1), a low energetic cost of 36-55 kJ mol(-1) and an extremely low capacity fade rate of <0.01% per day, depending on organic concentration. The system charge-discharge cycle provides an electrical energy storage function that could be run only for storage when called for by electricity market conditions.