A rechargeable Na–CO2/O2 battery enabled by stable nanoparticle hybrid electrolytes

Abstract

We report on rechargeable batteries that use metallic sodium as the anode, a mixture of CO₂ and O₂ as the active material in the cathode, and an organic–inorganic hybrid liquid as electrolyte. The batteries are attractive among energy storage technologies because they provide a mechanism for simultaneously capturing CO₂ emissions while generating electrical energy. Through in and ex situ chemical analysis of the cathode we show that NaHCO₃ is the principal discharge product, and that its relative instability permits cell recharging. By means of differential electrochemical mass spectrometry (DEMS) based on ¹²C and ¹³C we further show that addition of as little as 10% of 1-methyl-3-propylimidazolium bis(trifluoromethanesulfone)imide ionic liquid tethered to SiO₂ nanoparticles extends the high-voltage stability of the electrolyte by at least 1 V, allowing recharge of the Na–CO₂/O₂ cells.