Electrochemical performance of Al-substituted Li3V2(PO4)3 cathode materials synthesized by sol-gel method
(1. School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education,
Guilin University of Technology, Guilin 541004, China;
3. Guangxi Key Laboratory of Environmental Engineering, Protection and Assessment,
Guilin University of Technology, Guilin 541004, China;
4. College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China;
5. Hunan Institute of Humanities, Science and Technology, Loudi 417000, China)
2. Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education,
Guilin University of Technology, Guilin 541004, China;
3. Guangxi Key Laboratory of Environmental Engineering, Protection and Assessment,
Guilin University of Technology, Guilin 541004, China;
4. College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China;
5. Hunan Institute of Humanities, Science and Technology, Loudi 417000, China)
Abstract: The effect of Al-substitution on the electrochemical performances of Li3V2(PO4)3 cathode materials was studied. Samples with stoichiometric proportion of Li3AlxV2−x(PO4)3 (x=0, 0.05, 0.10) were prepared by adding Al(NO3)3 in the raw materials of Li3V2(PO4)3. The XRD analysis shows that the Al-substituted Li3V2(PO4)3 has the same monoclinic structure as the un-substituted Li3V2(PO4)3. The SEM images show that Al-substituted Li3V2(PO4)3 has regular and uniform particles. The electrochemical measurements show that Al-substitution can improve the rate capability of cathode materials. The Li3Al0.05V1.95(PO4)3 sample shows the best high-rate performance. The discharge capacity at 1C rate is 119 mA∙h/g with 30th capacity retention rate about 92.97%. The electrode reaction reversibility and electronic conductivity are enhanced, and the charge transfer resistance decreases through Al-substitution. The improved electrochemical performances of Al-substituted Li3V2(PO4)3 cathode materials offer some favorable properties for their commercial application.
Key words: lithium ion batteries; cathode material; Li3V2(PO4)3; electrochemical performance; sol-gel method