With the rapid growth of retired lithium-ion batteries (LIBs), the recycling of electrode materials has become a hot topic in research. Considering the economic factors, the recovery of cathode electrodes has always been the focus of research. Until now, the recovery of anode electrode materials has gained much attention due to their large proportion in batteries. This research focuses on the recovery and regeneration of anode graphite. Based on the existing form of lithium in anode graphite carbon powder, environmentally friendly citric acid is selected as the extraction reagent to extract lithium and regenerate spent graphite. Through orthogonal experiments and conditional experiments, the optimal conditions for extracting the lithium element from the spent LIB anodes were a temperature of 90 °C, S/L ratio of 1:50 g mL–1, C AC of 0.2 mol L–1, and time of 50 min, and the leaching rate of lithium ions can reach 97.58%. The electrochemical performance tests showed that the regenerated graphite anode material after the extraction of lithium had a high discharge capacity of 330 mA h g–1 after 80 cycles at 0.5 C, and the Coulombic efficiency is maintained above 99%. By comparing the regenerated graphite and the pretreated spent graphite, the regenerated leached graphite has obviously excellent electrochemical performance, and its properties can be comparable to those of artificial graphite. This experimental result provides a theoretical basis for the subsequent recycling of anode electrode graphite.

Ni-rich LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM) material has attracted intense attention because of the capacity and cost advantages. However, the poor cycling performance hampers the further development of NCM. As a coating layer, polysiloxane can improve the electrochemical properties of the NCM by eliminating remaining H 2 O on the surface of NCM and the reaction between HF in electrolyte and NCM, inhibiting the interfacial side reactions. Compared with the pristine NCM, the cycling performance of the NCM cathode coated with polysiloxane is significantly improved. The capacity retention of NCM coated with polysiloxane is 91.5% at 1 C after 120 cycles, while pristine NCM only maintains 71.4%. This study provides a method to alleviate the effects of interfacial side reactions and HF corrosion on NCM performance degradation after many cycles.

Anodes composed of Mn3O4 deliver a much higher specific capacity in Li-ion batteries (LIBs) than that of commercial graphite but suffer from poor cycling stability, a poor rate characteristic, and a high overpotential stemming from volumetric changes during cycling, low electroconductibility, and insufficient ion diffusivity. To make Mn3O4 more applicable, we developed a convenient one-pot synthesis route to fabricate porous hierarchical spherical Mn3O4 with in situ coated conductive carbon (C-Mn3O4). The C-Mn3O4 shows a large capacity and good cycling stability. When assembled into anodes, this material delivered a capacity of 703 mA h g–1 in a 1000 mA g–1 cycling test after 700 cycles with only a 3% capacity decay. Meanwhile, the system provided superior rate performance with capacities of 860, 823, 760, 674, and 570 mA h g–1 at 100, 200, 500, 1000, and 2000 mA g–1, respectively. On the basis of our systematic investigations, we attribute this high electrochemical performance to the carbon reinforced porous hierarchical sphere structure.

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