A rechargeable liquid metal–CO2 battery for energy storage and CO2 reduction to carbon

Abstract

A new type of high-temperature liquid gallium–CO₂ battery (LGaCB) is demonstrated to overcome the major limitations of slow reaction kinetics and inactive solid blockage of electrodes associated with the current solid metal–CO₂ batteries (MCBs). The LGaCB has exhibited power densities that are over an order of magnitude higher than the best of existing MCBs. The LGaCB operates by unique mechanisms enabled by CO₃²⁻ conduction through molten carbonate electrolyte and Ga self-catalyzed CO₂ reduction, which discharge Ga₂O₃ nanoparticles (dia. ∼20 nm) and large chunks of carbon (>50 μm) in the liquid Ga (LGa). In the charging process, the Ga₂O₃ nanoparticles dispersed in the LGa are reduced without significant reverse oxidation of carbon that leads to an overall carbon-negative effect.