Electrochemical exfoliation of graphite recovered from spent Li-ion batteries and its reuse as graphene in new electrodes

The growing demand for lithium-ion batteries, driven by the increasing number of electric vehicles, has led to rising volumes of end-of-life battery waste. In this work, a sustainable approach was developed for recovering graphite from spent LIBs and converting it into high-value electrode materials for electrochemical double-layer capacitors (EDLCs). Graphite was extracted from the anodes of spent NMC cells and functionalized via anodic electrochemical exfoliation under conditions optimized using the Taguchi method. The exfoliation parameters, namely applied potential, time, and temperature, were systematically studied to enhance the electrochemical performance of the resulting graphene oxide-based materials. The best-performing sample achieved a specific capacitance of 21 F g −1 at 0.1 A g −1 and retained 91 % of its initial capacitance after 10,000 charge/discharge cycles at 8 A g −1 . Additionally, a symmetric supercapacitor cell assembled using the optimized sample (E9) demonstrated comparable performance to commercial activated carbon (YP50), confirming its practical viability. This study highlights the potential of recycled graphite as a sustainable precursor for graphene-based electrodes, contributing to the development of environmentally friendly energy storage technologies, aligned with circular economy principles.