Study on high-performance lithium-ion battery anode material with semi-crystalline nanocarbon layer coating on regenerated graphite

Abstract

After the regeneration of graphite anode material from spent lithium-ion batteries, it generally meets the requirements for conventional applications; however, the regenerated graphite still has potential for further optimization in terms of cycle stability and rate performance. In this paper, a high-performance anode material is successfully prepared using a liquid-phase coating method, with special spinnable pitch as the external carbon source and regenerated graphite as the core. The results show that after high-temperature treatment, the Semi-Crystalline nanocarbon layer generated from the spinnable pitch effectively covers the surface of the regenerated graphite matrix and fills the surface pores and defects in the graphite material, forming a unique “core–shell” structure composite. After assembling a full-cell, the initial charge capacity at 0.1C was 144.1 mAh/g, with a capacity retention rate of 93.3 % after 400 cycles. The Li⁺ diffusion coefficient was 1.741 × 10⁻⁸ cm²/s, and the charge transfer resistance (Rct) was 4.894 Ω. The development of this technology is of great significance for promoting the high-value recycling of spent lithium-ion battery graphite anode materials, strengthening the collaboration between upstream and downstream industries, and facilitating the development of the circular economy.