In Situ Aluminothermic Reduction Induced by Mechanochemical Activation Enhances the Ability of the Spent LiCoO2 Cathode to Activate Peroxymonosulfate

The application of the cathode of spent lithium-ion batteries (LIBs) in advanced oxidation processes (AOPs) is limited due to its low utilization rate and low catalytic efficiency. Thus, in situ aluminothermic reduction induced by mechanochemical activation (MCA) was proposed to improve the catalytic effect of the spent cathode. In this study, an aluminum foil in the cathode of spent LiCoO2 batteries was used as a reducing agent for the first time for the MCA process, which realized the efficient utilization of the spent cathode and avoided the waste of aluminum resources. The results showed that MCA significantly improved the catalytic rate and catalytic stability. The degradation rate of o-phenylphenol can reach 100% within 30 min. After five cycles, the degradation rate can still be maintained at about 96%. This result could be ascribed to the fact that the aluminum foil can be used as a reducing agent. In MCA, part of Co3+ was transformed into Co2+. Meanwhile, the change in the pore structure, the increase in oxygen and metal cation vacancies, and the acceleration of the electron transfer rate improved the catalytic performance. This method provides a new idea for the efficient recovery and application of spent LIBs, which extends the application scope of spent LIBs in the environmental field.