Effective regeneration of mixed composition of spent lithium-ion batteries electrodes towards building supercapacitor

Recycling of different manufacturers of spent lithium-ion batteries cathode and anode via a simple regeneration process has an opportunity to fabricate new energy devices. In this study, the different manufacturers of spent LIB cathode pieces were subjected to lixiviation process and found the best-optimized conditions such as tartaric acid concentration (2.5 M), H₂O₂ concentration (7.5 vol%), solid-liquid ratio (80 g/L), temperature (80 °C), and lixiviation time (80 min) for maximum ~ 99% extraction efficiency of metals. Further, 3D-MnCo₂O₄ (MCO) spheres were regenerated from the cathode lixivium containing metal ions via hydrothermal technique. Besides, anode graphite and Al foils after cathode lixiviation were exploited to prepare reduced graphene oxide (RGO) at room temperature in a simple method. The electrochemical performance of both regenerated electrodes from spent LIBs was explored in the half-cell configuration using the 1 M Na₂SO₄ electrolyte. Additionally, the constructed MCO//RGO asymmetric supercapacitor device offers an operational voltage of 1.8 V and displays a high energy density of ~ 23.9 Wh kg^-1 at 450 W kg^-1 with 8000 cycles. This alternative recycling method proposes the possibility to construct high-energy storage devices from different compositions of spent LIBs.