Upcycling of Low-Value Cathode Materials from Spent Lithium-Ion Battery to High-Voltage Cathode with Ultrahigh Rate Capability and Reversibility

Abstract

LiMn₂O₄ and LiFePO₄ materials are widely applied in electric vehicles and energy storage. Currently, spent LiMn₂O₄ and LiFePO₄ materials recycling is challenged by long process, high energy consumption, and poor recycling economy due to the indispensable metal separation in their recycling. Aiming at this challenge, an upcycling of low-value cathode materials to high-value high-voltage lithium ferromanganese phosphate (LMFP) by simple leaching and hydrothermal reaction is proposed, and the LMFP material with ultrahigh rate capability and reversibility due to its homogenized element distribution, well-defined nanorods particles, short Fe/Mn─O bond and long average Li─O bond length is regenerated. The initial discharge capacity reaches 144.2 mAh g⁻¹ with 87% capacity retention after 1000 cycles at 1 C. Even cycling at 5 C, a discharge capacity of 136.9 mAh g⁻¹ with 86.4% capacity retention is achieved after 1000 cycles. Kinetics analysis and characterizations of the regenerated LMFP material after cycling further reveal its fast diffusion ability and stable structure. This work sheds light on the potential value of LMFP material regeneration and offers an economic strategy for upcycling of spent low-value cathode materials.