Direct regeneration of high-value LiFePO4 cathode materials with nitrogen doped carbon coating

Abstract

Lithium iron phosphate (LiFePO4) batteries are currently becoming the primary power system for electric vehicles. However, after the life period, the heavy amounts of electric cars would give rise to a great number of scrapped LiFePO4 batteries, which inevitably causes serious environmental pollution and resources waste problems. Therefore, it is much imperative and urgent to develop the green technology for regenerating and recycling these scrapped LiFePO4 batteries. Herein, we reported an efficient and straightforward solid-phase strategy to achieve the direct regeneration of scrapped LiFePO4 cathode materials. The decommissioned LiFePO4 was successfully regenerated by adding lithium carbonate and melamine under the heat treatment condition, and the battery performance was repaired. The electrochemical performance of regenerated LiFePO4 is even higher than that of the unused LiFePO4 at 0.05 C. Moreover, the regenerated LiFePO4 also exhibits excellent capacity preservation rate of 99.03 % after 200 cycles and outstanding rate capability at 5 C with a discharge capacity of 116 mAh/g. The systematical study demonstrates that the nitrogen-doped carbon coatings play vital role in improving the properties of regenerated LiFePO4 cathode materials. This work provides a potential approach to resolve the scrapped LiFePO4 cathode materials to meet the coming retired tide of lithium ion batteries.