A new electrolyte for molten carbonate decarbonization

Abstract The molten Li 2 CO 3 transformation of CO 2 to oxygen and graphene nanocarbons (GNCs), such as carbon nanotubes, is a large scale process of CO 2 removal to mitigate climate change. Sustainability benefits include the stability and storage of the products, and the GNC product value is an incentive for carbon removal. However, high Li 2 CO 3 cost and its competitive use as the primary raw material for EV batteries are obstacles. Common alternative alkali or alkali earth carbonates are ineffective substitutes due to impure GNC products or high energy limitations. A new decarbonization chemistry utilizing a majority of SrCO 3 is investigated. SrCO 3 is much more abundant, and an order of magnitude less expensive, than Li 2 CO 3 . The equivalent affinities of SrCO 3 and Li 2 CO 3 for absorbing and releasing CO 2 are demonstrated to be comparable, and are unlike all the other alkali and alkali earth carbonates. The temperature domain in which the CO 2 transformation to GNCs can be effective is <800 °C. Although the solidus temperature of SrCO 3 is 1494 °C, it is remarkably soluble in Li 2 CO 3 at temperatures less than 800 °C, and the electrolysis energy is low. High purity CNTs are synthesized from CO 2 respectively in SrCO 3 based electrolytes containing 30% or less Li 2 CO 3 .