Low-carbon and energy-efficient strategy to convert CO2 into carbons with tunable graphitization degree as lithium storage materials toward ultra-long cycle life

Converting greenhouse gas CO2 into high-performance energy storage materials is of great significance due to its capability of simultaneously addressing environmental issues and energy crises. However, great challenges still remain for the low-carbon and energy-efficient conversion of CO2. Herein, we report an energy-efficient and time-saving strategy for converting CO2 into carbon materials by the reaction of CO2 with Mg(AlH4)2 at about 126–136 ℃ in seconds. The chemical reaction of CO2 with Mg(AlH4)2 is reported for the first time. Importantly, the graphitization degree and pore structure of as-synthesized carbon materials are found to be regulated by CO2 pressure. As a lithium storage application, the graphitization degree-dependent electrochemical performance is revealed for the carbon anodes. The highly graphitized carbon prepared at high CO2 pressure exhibits high capacity and ultra-long cycle life, delivering a high reversible capacity of 487 mAh g−1 at 1.0 A g−1 after 3500 cycles. This study develops a green and low-temperature strategy to synthesize CO2-derived carbon materials with tunable graphitization degree for energy storage.