Ti含量对掺杂磷酸铁锂正极材料性能影响的研究

Effect of Ti Content on the Properties of Doped Lithium Iron Phosphate Cathode Materials

采用湿法高能球磨和高温固相的方法,合成了不同Ti含量掺杂的锂离子电池正极材料磷酸铁锂,并通过粉末X射线衍射(XRD)、扫描电镜(SEM)、等离子电感耦合(ICP)、碳硫测试仪和电性能测试对该材料进行表征和测试。结果表明,Ti掺杂并不影响磷酸铁锂材料的晶体结构;随着Ti含量的升高,一次颗粒明显变小;碳含量逐渐升高。电化学性能测试表明,在0.2 C和20 C下的最高放电容量能达到163 m Ah g^(-1)和118 m Ah g^(-1),验证了Ti离子主要对磷酸铁锂的高倍率性能产生较为严重的影响,其可广泛应用于高功率领域的电池系统中。

LiFePO4/C cathode materials with different Ti doped for lithium-ion batteries were prepared by a wet high-energy ball-milling and solid-state method under N2atmosphere.The samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),ICP and galvanostatic charge-discharge test.Results indicated that no change was occurred for LiFePO4crystal and smaller primary particle size with increasing Ti content for LiFePO4/C composites.Highest discharge capacities of163mAh g^-1and118mAh g^-1were obtained at the rates of0.2C and20C for half-cell tests,respectively,making it applicable in electric vehicle(EV)/hybrid electric vehicle(HEV)and energy storage systems on a large scale.