Dopant And Modification Of LiFePO₄/C Cathode Material For Lithium-ion Batteries

In this paper,LiFePO4/C materials were prepared by high temperature mechanical chemical method.Fe2O3,Li2CO3,phosphoric acid and glucose were used as raw materials.LiFePO4/C powders acquired at 670℃ for 15 h.Molar ratio Li:Fe was 1:0.975.Balls/material weight ratio was 15:1.This paper studied the amount of carbon coating,the choice of dopants,the quality of dopants on the ratio in-depth.And this paper studied the effect of water-based adhesives and oil-based binders on the performance of lithium iron phosphate batteries.The characterization of t the cathode materials were studied by X-ray diffraction(XRD),scanning electron microscopy(SEM),charge-discharge test(CD),cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS),laser particle size measurement(PSD).LiFePO4 composites were prepared by carbon coating and doping LiF and doping H2TiO3/V2O5/MgO/Al2O3.The results showed that the LiFePO4/C cathode material with a carbon content of 4 wt.%had a good electrochemical performance.The first discharge was 127.6 mAh/g.After 20 cycles,the discharge capacity reached 91.23%of the initial capacity.On this basis,doping metal ions,the cathode material doped with vanadium had a better electrochemical activity,LiFe0.975V0.025PO3.99F0.01/C cathode material had no impurity peak,and had a good rate performance and cycle performance.The discharge capacity retention rate at the different magnification was 97.38%,97.73%,and the discharge capacity retention rate was 97.38%,97.33%,99.28%.Based on the above research,the effect of binder on lithium ion batteries was investigated by using different binders.This paper studied that the oil-based system(PVDF)and water-based system(LA132)effect the properties.The results showed that LA132-LFP had higher specific capacity but it had severe polarization.