Sustainable Regeneration of High-Performance Li1–xNaxCoO2 from Cathode Materials in Spent Lithium-Ion Batteries

With the wide implication of lithium-ion batteries (LIBs), the recycling of spent LIBs has generated strong concern in alleviating resource shortage and environmental pollution. In this work, the Li 1– x Na x CoO 2 ( x = 0, 0.01, 0.03, and 0.05) cathode materials with structural repair and electrochemical performance improvement were obtained from degraded LiCoO 2 cathodes (Li loss of >50% and capacity reduction of about 65%) in combination with relithiation regeneration and modification. Compared with regenerated LiCoO 2 (RLCO) and commercial LiCoO 2 (CLCO) materials, the Li 1– x Na x CoO 2 cathodes show a neat and ordered layered structure, better discharge capacity, and cycle stability, especially at high current density and high voltage. The initial discharge capacities of Li 0.99 Na 0.01 CoO 2 (NLCO0.01) and RLCO are 151.5 and 149.4 mA h g –1 at the rate of 1C, respectively, which is almost three times higher than that of degraded LiCoO 2 (50.5 mA h g –1 ). Moreover, the capacity retention rate after 100 cycles of NLCO0.01 at the rate of 10C is as high as 87.6%, vastly superior to the 63.2 and 54.2% retention rates of RLCO and CLCO, respectively. The excellent rate performance and cycle ability are attributed to the expansion of lithium layer spacing caused by sodium-ion doping with a larger radius and faster Li + diffusion kinetics in the NLCO0.01 sample. This work provides a simple and effective strategy to regenerate and modify spent cathode materials, which provides a reference for the disposal of spent LIBs henceforth.