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Graphite is the state-of-the-art anode material for most commercial lithiumion batteries. Currently, graphite in the spent batteries is generally directly burned, which caused not only CO 2 emission but also a waste of precious carbon resources. In this study, we regenerate graphite in lithium-ion batteries at the end of life with excellent electrochemical properties using the fast, efficient, and green Flash Joule Heating method (FJH). Through our own developed equipment, under constant pressure and air atmosphere, graphite is rapidly regenerated in 0.1 s without pollutants emission. We perform a detailed analysis of graphite material before and after recovery by multiple means of characterization and find that the regenerated graphite displays electrochemical properties nearly the same as new graphite. FJH provides a large current for defect repair and crystal structure reconstruction in graphite, as well as allowing the SEI coating to be removed during ultra-fast annealing. The electric field guide the conductive agent and binder pyrolysis products to form conductive sheet graphene and curly graphene covering the graphite surface, making the recycled graphite even better than new commercial graphite in terms of electrical conductivity. Regenerated graphite has excellent multiplier performance and cycle performance (350 mAh g À1 at 1 C with a capacity retention of 99% after 500 cycles). At cost, we get recycled graphite that displays the same performance as new graphite, costing just 77 CNY per ton. This FJH method is not only universal for the regeneration of spent graphite generated by various devices but also enables multiple use-failure-regeneration steps of graphite, showing great potential for commercial applications.

In this report, the electrochemical behaviors of Pr(III) and Ni(II) ions on a W electrode were investigated in LiCl-KCl eutectic by cyclic voltammetry (CV), square wave voltammetry (SWV), chronopotentiometry (CP) and open-circuit chronopotentiometry (OCP) techniques. From the results of electrochemical methods, different signals corresponding to seven kinds of intermetallic compounds in the phase diagram of PrÀ Ni were observed. The thermodynamic properties of intermetallic compounds in the temperature range of 823-923 K were investigated by open-circuit chronopotentiometry. With the eval-uated apparent standard potentials of PrÀ Ni intermetallic compounds, the Gibbs energies, enthalpies and entropies of formation were also calculated. The co-reduction products by galvanostatic and potentiostatic electrolysis were characterized based on X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS). The shape of the alloy obviously changes from granular to bulk, and the alloy phase changes from Pr-rich to Ni-rich. The co-reduction products of PrNi 5 , PrNi 2 and PrNi were identified.