Direct Power Charge and Discharge Using the Glycolic Acid/Oxalic Acid Redox Couple toward Carbon-Neutral Energy Circulation

We demonstrated an electric power circulation method that does not emit CO2 and is based on the glycolic acid (GC)/oxalic acid (OX) redox couple. Electric power charge in GC was achieved through OX electro-reduction with high selectivity (>98%) using purely anatase-type TiO2 spheres in the potential region of -0.5 to -0.7 V vs. RHE at 50 ºC. We also realized GC production via the combination of electrochemical OX reduction and electro-oxidation of water with the help of renewable light energy for the first time. Furthermore, we succeeded in power generation via the selective electro-oxidation of GC to OX without CO2 emission. These results are the first experimental proof of the carbon-neutral power circulation involving an alcohol/carboxylic acid redox couple.