Modification Of Lithium Vanadium Phosphate Anode Material For Lithium Ion Battery

3is given close attention in recent years because of its high working voltage and large specific capacity. But its low electronic conductivity affects the rate capacity performance. This article mainly studies the modification of Li3V2(PO4)3through liquid phase method to improve electrochemical properties.In our study, sub-micron Li3V2(PO4)3/C was synthesized by novel solution-phase method with the assistant of surfactant P123(EO20PO70EO20). The influences of different synthetic temperature and different amount of P123addition on the structure, morphology and electrochemical performance of the sample were systematically investigated. And electrochemical perfomance of synthetic samples in optimum conditions were further studied. The results showed that:The sample with addition of30wt%P123in the precursor and then calcined at850℃had complete crystal growth, rather small size and performed the highest first discharge capacity,128.7mAh·g-1at0.1C,104.3mAh·g-1at5C in the range of3～4.3V. At0℃and40℃, the first discharge capacity of the sample were102.9mAh·g-1and131.2mAh·g-1respectively, the sample capacity retention rate of low temperature was78.4%, indicating that the low temperature performance of this material should be improved. The sample capacity retention rate achieves more than90%at different testing temperature and different discharge rate after50cycles, It proved that this material had good circulation performance.Then the step-by-step method of liquid phase was used to synthesis Li3V2(PO4)3/(C+CuO) on the basic of adding copper acetic to Li3V2(PO4)3/C. The influence of different amount of copper acetate adding on crystal structure and electrochemical properties was studied. The results showed that:with the increase of copper acetate, the sample discharge capacity increased at first and then decreased, the Li3V2(PO4)3/(C+CuO) with3mol%copper acetate adding growed complete crystal, and its surface was rough then Li3V2(PO4)3/C’s. The first discharge capacity of Li3V2(PO4)3/(C+CuO) with3mol%copper acetate adding was close to the theoretical value,131.8mAh·g-1at0.1C in the range of3-4.3V, and the retention rate was95.2%after100cycles. The sample discharge capacity at2C was90.4%of0.1C, cyclic voltammogram(CV) test indicated that the sample had good reversibility.