Sodium-Gallium Liquid Metal Enables Mild-Condition Co2 Conversion to Solid Carbon for Sustainable Electrode Materials

Abstract

Developing innovative carbon capture and utilization technologies is crucial for achieving carbon neutrality. Reducing CO2 to solid carbon is an important strategy for sustainable development. However, this process typically requires harsh reaction conditions and suffers from material instability. To meet this challenge, we present a novel Na-Ga liquid metal system capable of efficiently reducing CO2 to solid carbon under mild reaction conditions at ambient pressure. Na dissolved in liquid Ga can avoid direct contact with air, thereby ensuring the stability of the reaction. At 600 °C and ambient pressure, approximately 1 mg of solid carbon is generated for every 5 mg of Na consumed. Density functional theory (DFT) calculations further reveal the role of Na-Ga alloys in facilitating C–O bond cleavage. The resulting solid carbon is readily separable from the alloy surface and demonstrates exceptional electrochemical performance as an electrode material. Moreover, the liquid metal is efficiently recovered through an acid-washing process, enabling reuse and enhancing resource utilization. Compared to traditional methods, this innovative approach offers crucial scientific and technical support for developing cost-effective and scalable carbon-neutrality technologies with potential applications in energy storage and industrial sustainability.

Keywords: CO2 reduction, solid carbon, liquid metal, Na-Ga alloy, electrode materials