For regenerated graphite: Tailoring sub-surface architecture with strong pre-storage abilities towards high-rate properties

Abstract

Captured by the economic value and environmental friendliness, the high-value recycling of spent batteries has been devoted plenty of attention. However, the regenerated graphite is still limited by large anisotropy and inferior rate abilities. Through the tailoring of low-temperature ionic liquid, the further regenerated graphite displayed rich sub-surface pores and improved crystalline degree, bringing about strong wettability and enhanced isotropy. Utilizing as lithium-storage anode, the optimized sample could deliver a capacity of 321 mAh/g after 300 loops at 1.0 C. Even at 2.0 C after 400 cycles, their capacity could also remain about 278 mAh/g. Supported by the detailed kinetic analysis, the abundant pores of sub-surface served significant roles in the enhancements of diffusion/surface-controlling behaviors. Their pre-storage advantages would be beneficial for the alleviation of voltage dropping, resulting in improved rate properties. Meanwhile, its activation energy was calculated at about 14.52 KJ mol−1, revealing its relatively small ion-diffusion energy barrier. More significantly, assisted by economic analysis, its revenue could also reach up to 5700$ t−1, with a promising recycling value. Given this, the work is expected to offer significant cooperative regeneration manners and shed light on the significant effect of sub-surface designing.