For High Capacity: Upcycling of Spent Graphite Catalytic via Precisely Tailoring Water-Gas Reaction

Considering their enormous economic and environmental value, the regeneration of spent graphite has been devoted to numerous attentions. However, limited by the sluggish kinetic behaviors of carbon atoms in bulk-phase, the high energy-consumption is always necessary, especially due to their serious surface fading. But, without effective activation, their surface remains electrochemically inert. Herein, assisted by water-gas reaction with the tailoring of cation and anion, the ion-regulation strategy is utilized to in-situ improve the regenerated energy-storage properties. Benefiting from suitable bond energy (390 kJ/mol) and activation energy (17.7 eV), Cl^- anions serve as an effective catalyst for water-gas interfacial reaction, and Na⁺ offers balanced solution resistance (2.57 Ω), enabling optimal synergy with Cl^- to construct active porous sub-surface (< 0.7 nm). After optimizing, the regenerated graphite delivers a reversible capacity of 392.8 mAh g^{- 1} after 300 cycles at 1.0 C with nearly 100% capacity retention, and retains 188.1 mAh g^{- 1} even at 5.0 C. Economic and environmental assessments reveal that the proposed methods consume only 3.5 MJ kg^{- 1} of energy and emit 0.5 kg kg^{- 1} of greenhouse gases. This work is expected to provide a promising novel pathway for the high-performance and controllable regeneration of spent graphite.