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

Abstract

AbstractCaptured 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 ≈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 ≈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.