From Waste to Energy—Extraction of Mesoporous Nanocomposites from Spent Li-Ion Batteries for High-Performance Supercapacitor Devices with Ultra-High Stability

Lithium-ion batteries (LIB) are one of the most significant energy storage devices used nowadays. However, a huge number of spent batteries bring harmful resource waste and environmental hazards due to heavy metals and organic electrolytes. Consequently, recycling spent LIB has become a hot topic lately, where researchers are actively working to develop a plethora of methods to extract valuable metals and components. In this study, mesoporous Li-Ni-Mn-Co oxide nanoparticles have been successfully extracted from spent Li-ion batteries using a simple microwave/precipitation method. The extracted Li-Ni-Mn-Co oxides were used to construct functional supercapacitor devices. However, the extracted oxides showed poor stability and low conductivity. To enhance cycling stability and conductivity, fullerene (C76) is used as a carbon additive to form Li-Ni-Mn-Co oxide/C76 nanocomposite material. The morphological, structural, and compositional analyses were performed using FESEM, HRTEM, XRD, and XPS techniques. The Li-Ni-Mn-Co oxide/C76 nanocomposite exhibits high conductivity and high wettability with an enhanced gravimetric capacitance of ~357 Fg-1 at 1.0 Ag-1. The asymmetric supercapacitor devices deliver specific energy as high as ∼21.3 Wh/kg at a specific power of ∼800 W/kg and a superior retention rate of ~115% after 20,000 cycles with ~100% Coulombic efficiency.