Molten salt electrochemical upcycling of CO₂ to graphite for high performance battery anodes

The efficient transformation of CO₂ into a value-added material is a potential strategy to help mitigate climate effects caused by CO₂ emissions. One potential CO₂ conversion product is graphite which is an important and versatile material extensively used in many applications including as an anode for lithium-ion batteries (LIBs). Commercial graphite, however, is traditionally synthesized via the energy intensive Acheson process (>3000 °C) and the performance of such graphite can be limited under fast charging conditions which is important for vehicle electrification. Herein, we report the electrochemical transformation of CO₂ to highly crystalline nano-graphite with a controlled microstructure in a carbonate molten salt at 780 °C. The use of a nickel foam electrode and controlled electrochemical parameters during the molten salt conversion process yielded pure graphite at a lower temperature compared to the Acheson process. Moreover, when investigated as an anode material for LIBs, the CO₂-converted graphite exhibited high reversible capacity, long cycle life, and excellent rate capability even under fast charging conditions. This process provides a way to potentially reduce carbon emissions through the utilization of waste CO₂ by converting it into value-added graphite suitable for fast charging, high-energy-density batteries for vehicle electrification.