From Spent Lithium-Ion Batteries to Low-Cost Li 4 SiO 4 Sorbent for CO 2 Capture.

The huge consumption of fossil fuels leads to excessive CO 2 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 CO 2 -capturing materials to put the latter into implementation. Herein, for the first time, we propose a route to synthesize low-cost Li 4 SiO 4 as CO 2 sorbents from spent LIBs, verify the technical feasibility, and evaluate the CO 2 adsorption/desorption performance. The results show that Li 4 SiO 4 synthesized from the cathode with self-reduction by the anode graphite of LIBs has a superior CO 2 capacity and cyclic stability, which is constant at around 0.19 g/g under 15 vol % CO 2 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 Li 4 SiO 4 sorbents, and thus could be of great significance for the development of CO 2 adsorption.