CO2-ammonia battery using organic proton-coupled electron transfer

CO2 batteries offer a promising solution for mitigating climate change by reducing CO2 emissions. Using ammonia, a highly effective gaseous alkali, we can harness chemical energy through its reaction with CO2 for power generation. However, the lack of direct electron transfer in the ammonia-CO2 carbonation reaction and ammonia's susceptibility to precious metal catalysis side reactions and corrosion complicate the construction of an efficient battery system. To overcome these challenges, we propose a concept that uses organic catalytic reactions to harness the chemical energy from the CO2-ammonia reaction for electricity generation. By employing isoalloxazine derivatives—riboflavin sodium phosphate (FMN-Na)—as proton carriers in redox reactions, we can create battery electromotive force through the proton concentration difference (ΔpH) between CO2 and ammonia. This approach leverages reversible electrochemical proton-coupled electron transfer (PCET) reactions to drive electron flow and facilitate power generation, without requiring renewable electricity charging. Our study demonstrates that a CO2-ammonia battery can achieve a peak power density of 22.5 W m−2, converting 1 ton of CO2 into 60.04 kWh of electricity while producing over 99.60 % purity ammonium bicarbonate. Our work combines CO2 mitigation, electricity generation, and the production of valuable by-products, offering innovative strategies for addressing environmental and energy challenges simultaneously.