Large-Scale and Homogenized Strategies of Spent LiFePO₄ Recycling: Reconstruction of Targeted Lattice

Captured by the remarkable environmental/economic value, recycling spent LiFePO4 has attracted numerous attention. However, restricted by diverse failure mechanisms and different particle-sizes/active-sites, recycling strategies still suffer from uneven repairing results and poor accessibility. For promoting their application in commercial systems, the uniform physical-chemical properties are urgent for regenerated samples. Herein, by tailoring oxidation-reduction manners, the homogeneous cathode materials can be prepared, displaying uniform particle size and restored lattice. The capacity of as-optimized samples can be kept approximate to 141.5 mAh g(-1) at 1.0 C, and 137 mAh g(-1) with a retention of 92% after 300 cycles at 2.0 C. After Kg-scale experiments, the pouch full-cell (LFP-500 vs recovered graphite) delivers approximate to 4200 mAh capacity, with considerable cycling stability (retention 96.83%, after 500 loops). Importantly, the detailed mechanism of oxidation/reduction-conditions is investigated, especially their lattice reconstitution and ions- diffusion behaviors. Supported by kinetic analysis and DFT calculations, the fascinating stability of LFP-500 is further proved, mainly derived from the accelerated Li-diffusion behaviors. Compared to traditional recovering manners, oxidation/reduction process displays low cost, energy-consumption, and pollution, accompanied with considerable large-scale application potential. Given this, this work is anticipated to illustrate the in-depth mechanism of lattice-reconstruction, while offering significant strategies for large-scale and homogenized regeneration.