Pre‑Agglomeration Granulation for Fluidized Bed Sintering of Geldart Group C LiFePO 4 With Enhanced Electrochemical Performance
Siyang Liu, Yuze Zhao, Tengyue Ma, Xin Zhang, Jiancheng Zhang, Yanliang Wen, JianXue Deng, Hongyan Wang, Mingzi Hong, Fei WeiABSTRACT
Traditional static sintering of LiFePO 4 (LFP) in roller kilns suffers from low heat/mass transfer efficiency and uneven atmosphere distribution, leading to high energy consumption and inhomogeneous carbon coating. Fluidized‐bed sintering offers superior transfer kinetics, yet battery‐grade LFP belongs to Geldart Group C and is inherently non‐fluidizable. Herein, a pre‐agglomeration granulation strategy using glucose/poly(ethylene glycol) binders via spray drying successfully transforms LFP from Group C to Group A. Systematic comparison with static tube‐furnace sintering reveals that dynamic fluidized‐bed sintering promotes uniform Al 3+ doping, suppresses abnormal grain growth, and enables the formation of a uniform, continuous carbon layer (∼ 9 nm). Benefiting from these structural improvements, the sintered LFP exhibits a more uniform grain size distribution and a well‑integrated carbon coating. Electrochemical evaluation reveals a capacity retention of 77% at 5C and 94% after 400 cycles. The material achieves an ion diffusion coefficient of 9.66×10 −13 cm 2 s −1 . This work not only overcomes the fluidization barrier of LFP, enabling kinetic optimization, structural control, and performance enhancement, but also establishes a general route to convert non‐fluidizable Geldart C powders into fluidizable granules. The scalable and efficient fluidized‐bed process paves the way for green, continuous manufacturing of high‐performance LFP and other fine battery materials.