Modulating Bidirectional Catalytic Activity Through a RuNi Nanoalloy on Facile Candle Soot Carbon Towards Efficient Li‐CO2Mars Batteries

Li‐CO2 batteries have been at the forefront of reducing CO2 emissions and addressing the present energy crisis. As the Martian atmosphere is 95% CO2, this battery technology is ideal as a stand‐alone energy storage device on the planet. However, challenges such as low reversibility, high charging voltages, and poor cycling life restrict its practicability. The current study addresses these by increasing the reversibility of the active reaction sites on the cathode via a synergistic interaction between the RuNi nanoparticle catalyst and candle soot carbon (CSC). This helps the system achieve a full discharge capacity of 15207 mAh g‐1 at a high current density of 200 mA g‐1 with 99.3 % coulombic efficiency and an efficient cycling life of over 100 cycles at a higher current density of 500 mA g‐1 for a limited capacity of 500 mAh g‐1. Further, combining ex‐situ physical characterizations and density functional theory helps understand the underlying mechanism for improving the bidirectional CO2 reduction and evolution activities during discharging and charging. The study, thus using a bimetallic catalyst and carbon, provides an approach for a single solution towards addressing the dual challenges of regulating CO2 emissions on Earth and providing a constant energy source on Mars.