Upcycling of LiFePO 4 to high-performance LiMn x Fe 1− x PO 4 : activating the Mn redox platform for stable energy storage

at 5.0C, and 91.1% capacity retention after 500 cycles at 1.0C. The underlying phase transformation and Mn activation mechanisms during high-temperature calcination were systematically investigated, revealing critical insights into the structural evolution from LFP to LMFP. This work provides fundamental insights into the design of efficient upcycling strategies for transitioning low-voltage cathodes to advanced high-energy-density materials, offering both environmental and technological benefits for sustainable energy storage.