Enhanced cathode performance of LiFePO4/C composite by novel reaction of ethylene glycol with different carboxylic acids

In this paper, nano-scale LiFePO4/C composite was prepared by adding monocarboxylic acid (benzoic acid), dicarboxylic acid (oxalic acid) and tricarboxylic acid (citric acid) as additives in ethylene glycol. A systematic description of the impacts from the number of carboxyl groups on the morphology and electrochemical properties of LiFePO4/C composite in the ethylene glycol system was provided. And the significantly size reduction and similar morphology to uniform rice grain were observed after the surface grafting reaction of ethylene glycol with carboxylic acids on the LiFePO4/C particle surface. Furthermore, the experiments indicated regular changes in the dispersibility and electrochemical properties. The sample in which citric acid was added performed best in terms of dispersibility with the particle size of about 800 nm, and also good regarding electrochemical property with first discharge capacity of 148.13 mAh/g and coulombic efficiency of 97.97%. •Described the impacts from the carboxyl groups on LiFePO4 in the ethylene glycol.•The carboxylic acid and ethylene glycol underwent the Surface grafting.•The reaction improved the particle dispersibility and controlled particle size.•The sample in which citric acid was added performed best.•148.13 mAhg−1 initial discharge and 95.3% capacity retention were achieved.