Targeted regeneration and upcycling of spent graphite by defect-driven tin nucleation

Abstract

The recycling of spent batteries has become increasingly important owing to their wide applications, abundant raw material supply, and sustainable development. Compared with the degraded cathode, spent anode graphite often has a relatively intact structure with few defects after long cycling. Yet, most spent graphite is simply burned or discarded due to its limited value and inferior performance on using conventional recycling methods that are complex, have low efficiency, and fail in performance restoration. Herein, we propose a fast, efficient, and “intelligent” strategy to regenerate and upcycle spent graphite based on defect-driven targeted remediation. Using Sn as a nanoscale healant, we used rapid heating (~50 ms) to enable dynamic Sn droplets to automatically nucleate around the surface defects on the graphite upon cooling owing to strong binding to the defects (~5.84 eV/atom), thus simultaneously achieving Sn dispersion and graphite remediation. As a result, the regenerated graphite showed enhanced capacity and cycle stability (458.9 mAh g−1 at 0.2 A g−1 after 100 cycles), superior to those of commercial graphite. Benefiting from the self-adaption of Sn dispersion, spent graphite with different degrees of defects can be regenerated to similar structures and performance. EverBatt analysis indicates that targeted regeneration and upcycling have significantly lower energy consumption (~99% reduction) and near-zero CO2 emission, and yield much higher profit than hydrometallurgy, which opens a new avenue for direct upcycling of spend graphite in an efficient, green, and profitable manner for sustainable battery manufacture.