Simultaneous power generation and CO2 valorization by aqueous Al–CO2 batteries using nanostructured Bi2S3 as the cathode electrocatalyst

Abstract

There is an increasing awareness of the need to pursue energy solutions with a low carbon footprint. The conventional power generation process (e.g. combustion of fossil fuels) is typically accompanied by CO₂ emission. It would be very appealing if we can reverse this trend and achieve simultaneous power generation and CO₂ valorization. Herein, we demonstrate the first aqueous Al–CO₂ batteries using nanostructured Bi₂S₃ as the cathode electrocatalyst for selectively converting CO₂ to formate during discharge. Bi₂S₃ nanoplatelets are prepared via a facile solvothermal reaction. When measured in a flow cell configuration, they enable CO₂ reduction to formate with an excellent activity (current density up to >400 mA cm⁻²) and selectivity (∼100%). Aqueous Al–CO₂ batteries are assembled by pairing the Bi₂S₃ cathode and the Al anode. They exhibit an impressive power output as well as great formate production rate and selectivity at the cathode. Moreover, we demonstrate that it is possible to use scrap Al from used Al beverage cans for Al–CO₂ batteries to further lower the production cost.