Effects of Mg doping on the remarkably enhanced electrochemical performance of Na3V2(PO4)3 cathode materials for sodium ion batteries
Na3V2-xMgx(PO4)3/C composites with different Mg2+ doping contents (x=0, 0.01, 0.03, 0.05, 0.07 and 0.1) were prepared by a facile sol-gel method. The doping effects on the crystal structure were investigated by XRD, XPS and EXAFS. The results show that low dose doping Mg2+ does not alter the structure of the material, and magnesium is successfully substituted for vanadium site. The Mg doped Na3V2-xMgx(PO4)3/C composites exhibit significant improvements on the electrochemistry performances in terms of the rate capability and cycle performance, especially for the Na3V1.95Mg0.05(PO4)3/C. For example, when the current density increased from 1 C to 30 C, the specific capacity only decreased from 112.5 mAh g-1 to 94.2 mAh g-1 showing very good rate capability. Moreover, even cycling at a high rate of 20 C, an excellent capacity retention of 81% is maintained from the initial value of 106.4 mAh g-1 to 86.2 mAh g-1 at the 50th cycle. Enhanced rate capability and cycle performance can be attributed to the optimized particle size, structural stability and enhanced ionic and electronic conductivity induced by Mg doping.
- Beijing Inst. of Technology, Beijing (China). Key Lab. of Environmental Science and Engineering, School of Chemical Engineering and Environment
- Brookhaven National Lab. (BNL), Upton, NY (United States). Chemistry Dept.
- Publication Date:
- OSTI Identifier:
- Grant/Contract Number:
- AC02-98CH10886; 2015CB251100; NCET-12-0047; NCET-13-0033
- Accepted Manuscript
- Journal Name:
- Journal of Materials Chemistry. A
- Additional Journal Information:
- Journal Volume: 3; Journal Issue: 18; Journal ID: ISSN 2050-7488
- Royal Society of Chemistry
- Research Org:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Org:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- Country of Publication:
- United States
- 25 ENERGY STORAGE; national synchrotron light source
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