Tailored anion radii of molten-salts systems toward graphite regeneration with excellent energy-storage properties

Abstract

Graphite, as the typical non-renewable resource, low-cost recycling of graphite from spent lithium-ion batteries (LIBs) enjoys great significance in economic growth and resources reusing. However, the traditional regenerated manners still suffer from the incomplete repairing, especially the inferior isotropy. Herein, assisted by salt melt synthesis (SMS), the effect recycling process to repair spent graphite is successfully developed. Tailored by the melting-boiling points and ionic strength of molten salts, the as-regenerated graphite performed different repaired properties, including interlayer distance, grain size, and crystallinity, leading to a difference in electrochemical performance. As Li-storage anodes, the as-optimized sample displayed an attractive lithium-storage capability of 352 mAh g−1 after 200 loops at 1.0 C. Even at 5.0 C, it could exhibit about 175 mAh g−1. Simultaneously, supported by of detailed kinetic analysis, the evolutionary properties of molten liquid phase could improve interlayer isotropy, thereby enhancing rate performance. Moreover, for repairing spent graphite, the cost of the proposed process is 745.74 $ t−1, and the recycling profit for regenerating graphite is approximately 7200 $ t−1. Given this, this work was expected to offer the effective repairing manners of spent graphite, meanwhile demonstrating the feasibility about the molten salt approach.