超高压处理前驱体对LiFePO_4/C性能的影响

通过超高压处理溶胶-凝胶前驱体,以高温固相法制备磷酸铁锂(LiFePO_4)/C。用恒流充放电、循环伏安和交流阻抗等方法研究产物的电化学性能,并进行XRD、SEM等分析。超高压处理并没有改变LiFePO_4材料的晶体结构和充放电反应机理。与未经超高压处理的前驱体相比,超高压预处理的前驱体制备的材料粒径减小,均匀性提高,0.1 C首次放电容量达148.47 mAh/g、在平台电压范围内的放电容量增加约16.3 mAh/g,经过不同倍率共40次循环,容量保持率达98.2%,且倍率放电性能得到提高,欧姆阻抗和电化学反应阻抗减小。

Effect of ultrahigh-pressure treatment precursor on performance of LiFePO4/C

After a ultrahigh-pressure treating to the precursor prepared by sol-gel method,lithium iron phosphate(LiFePO4)/C was prepared by high temperature solid state method.The electrochemical performance of product was studied by galvanostatic charge/ discharge test,cyclic vohammetry and A.C.impedance.The structural and morphology were analyzed by XRD and SEM.Ultrahighpressure treatment did not change the crystal structure and charge-discharge reaction mechanism of LiFePO4.The particle size of target material prepared by ultrahigh-pressure treatment precursor was decreased and particle uniformity improved compared with the precursor without ultrahigh-pressure treatment.The initial specific capacity reached 148.47 mAh/g at rate of 0.1 C,increased by 16.3 mAh/g at the range of platform voltage.Mter 40 cycles at different rates,the capacity retention rate was 98.2％ and rate capability improved.Ohmic resistance and electrochemical reaction impedance decreased.