NaV_(1-x)Cr_xPO_4F的合成及电化学性能

Synthesis and electrochemical performance of NaV_(1-x)Cr_xPO_4F

采用高温固相法合成掺杂改性的NaV1-xCrxPO4F(x=0,0.04,0.08)作为钠离子电池正极材料。通过红外光谱(FT-IR)、X射线衍射(XRD)和扫描电镜(SEM)等对材料的晶体结构和形貌进行表征。从材料的晶体结构、恒流充放电测试和循环性能等方面分析掺杂元素Cr在改善材料性能中的作用。结果表明:掺Cr后的材料电化学循环稳定性得到较好的改善,首次放电容量达到83.3 mA.h/g,效率高达90.3%,循环20次后可逆容量保持率仍然有91.4%。

NaV1-xCrxPO4F（x=0, 0.04, 0.08） doped with Cr used for cathode of sodium-ion batteries was prepared by the high temperature solid-phase method. The structure and morphology of cathode materials were characterized by Flourier-infrared spectra （FT-IR）, X-ray diffractometer （XRD） and scanning electron microscope （SEM）. The effects of the Cr doping on the crystal structure, charge-discharge curves and cycle performances improvement of materials were analyzed. The results show that the as-prepared Cr-doped materials have better cycle stability characterization than the undoped one, the initial reversible capacity of 83.3 mA· h/g can be obtained, and the first efficiency reaches about 90.3%, and the capacity retention is still 91.4% after 20 cycles.