One‐Step Activation of Anode Materials from Spent Lithium‐Ion Batteries as High‐Performance Electrodes for Capacitive Deionization

Abstract

Mesophase microporous carbon spheres (MMCS), are the anode materials of spent lithium-ion batteries (LIB), existing in large amounts on the earth that result in resource wastes and ecological pollution. In order to utilize the above waste resources, a new idea of recycling scrapped LIB anode materials was exploited to apply for capacitive deionization (CDI). Herein, the activated microporous carbon spheres (AMCS) were synthesized by a one-step KOH activation of mesophase microporous carbon spheres (MMCS). By controlling the weight ratios of KOH to MMCS, the fabricated AMCS with the optimal specific surface area of 2626 m 2 g À 1 and the pore volume of 0.98 cm 3 g À 1 were fabricated. The AMCS3-1 with a weight ratio of KOH to MMCS of 3 : 1 exhibits higher specific capacitance (196.9 F g À 1) and lower charge transfer resistance. Importantly, the AMCS3-1 electrode demonstrates excellent electrosorption capacity of 12.73 mg g À 1 and fast salt adsorption rate of 2.64 mg g À 1 min À 1 at 1.2 V. In addition, the excellent repeatability over 50 regeneration cycles could be obtained for AMCS3-1 electrode compared with commercial activated carbon electrode. The results reveal that the AMCS3-1 is a promising candidate as high-performance electrodes for CDI. The strategy of recycling MMCS from waste LIB anode materials for CDI is desirable, which displays great potential in the removal of sodium chloride (NaCl).