Carbon dioxide (CO2) can be used as fuel in a battery made from easily obtainable materials, offering a novel approach to sequester CO2 emissions, according to researchers at Cornell University in the US. Wajdi Al Sadat and Lynden Archer constructed an electrochemical cell with metallic aluminium as the anode and a CO2/oxygen gas mixture as the active material in the cathode. Oxygen is reduced to form superoxide at the cathode, which then bonds to CO2 and combines with aluminium from the anode to make aluminium oxalate. For each kilogram of aluminium, more than 9 kg of CO2 can be captured from flue gas while providing 3.6 kWh of electricity – enough to make the new cell a potentially useful strategy to reduce CO2 emissions and produce power at the same time.