Optimized synthesis of LiFePO4 composites via rheological phase assisted method from FePO4 with acetic acid as dispersant

•LiFePO4 composites were prepared by rheological phase assisted method using acetic acid as dispersant.•Rheological phase assisted method avoided the sedimentation of the precursor during drying.•The optimal composites showed enhanced electrochemical performance as cathode materials.•This economic and facile method provides a promising alternative for large-scale production of LiFePO4.

LiFePO4 composites were synthesized by aqueous ball milling and carbon thermal reduction from FePO4·2H2O through a rheological phase using acetic acid as dispersant. The rheological phase assisted method using acetic acid as dispersant improved the homogeneity of mixing raw materials. Li deficiency and solid-solution Mg dopant in the lattice of LiFePO4 was created through controlled off-stoichiometry Li/Fe ratio. Li deficiency, solid-solution Mg doping and uniform carbon layer decreased electron transfer and Li-ion diffusion resistance. The optimal LiFePO4 composite exhibited a high rate capability with 153 mA·h·g−1 at 1 C and 111 mA·h·g−1 at 20 C as well as a stable capacity retention with 99% for 100 cycles at 2 C and 98% for 200 cycles at 5 C. The rheological phase assisted method from FePO4 with acetic acid as dispersant is a promising route for production of high quality LiFePO4 materials at a reasonable cost.