From Spent Lithium-Ion Batteries to Low-Cost Li₄SiO₄ Sorbent for CO₂ Capture

The huge consumption of fossil fuels leads to excessive CO₂ emissions, and its reduction has become an urgent worldwide concern. The combination of renewable energies with battery energy storage, and carbon capture, utilization, and storage are well acknowledged as two major paths in achieving carbon neutrality. However, the former route faces the discard problem of a large amount of lithium-ion batteries (LIBs) due to their limited lifespan, while it is costly to obtain effective CO₂-capturing materials to put the latter into implementation. Herein, for the first time, we propose a route to synthesize low-cost Li₄SiO₄ as CO₂ sorbents from spent LIBs, verify the technical feasibility, and evaluate the CO₂ adsorption/desorption performance. The results show that Li₄SiO₄ synthesized from the cathode with self-reduction by the anode graphite of LIBs has a superior CO₂ capacity and cyclic stability, which is constant at around 0.19 g/g under 15 vol % CO₂ after 80 cycles. Moreover, the cost of fabricating sorbents from LIBs is only 1/20-1/3 of the conventional methods. We think this work can not only promote the recycling of spent LIBs but also greatly reduce the cost of preparing Li₄SiO₄ sorbents, and thus could be of great significance for the development of CO₂ adsorption.