Chromium-based layered cathode materials suffer from the irreversible disproportionation reaction of Cr4+ to Cr3+ and Cr6+, which hinders the reversible multi-electron redox of Cr ions in layered cathodes, and limits their capacity and reversibility. To address this problem, a novel O3-type layer-structured transition metal oxide of NaCr1/3Fe1/3Mn1/3O2 (NCFM) was designed and studied as a cathode material. A high reversible capacity of 186 mA h g−1 was achieved at a current rate of 0.05C in a voltage range of 1.5 to 4.2 V. X-ray diffraction revealed an O3 → (O3 + P3) → (P3 + O3′′) → O3′′ phase-transition pathway for NCFM during charge. X-ray absorption, X-ray photoelectron and electron energy-loss spectroscopy measurements revealed the electronic structure changes of NCFM during Na+ deintercalation/intercalation processes. It is confirmed that the disproportionation reaction of Cr4+ to Cr3+ and Cr6+ can be effectively suppressed by Fe3+ and Mn4+ substitution. These results demonstrated that the reversible multi-electron oxidation/reduction of Cr ions can be achieved in NCFM during charge and discharge accompanied by CrO6 octahedral distortion and recovery.
|Number of pages||7|
|Journal||Journal of Materials Chemistry A|
|Publication status||Published - 2017|
Bibliographical noteFunding Information:
This work was financially supported by the NSAF (Grant No. 51502039 and U1430104), the National Key Scientific Research Project (Grant No. 2016YFB090150), and 1000 Youth Talents Plan and Science & Technology Commission of Shanghai Municipality (08DZ2270500). The work at Brookhaven National Laboratory was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy through the Advanced Battery Materials Research (BMR) Program under Contract No. DE-SC0012704. The authors acknowledge technical support by beamline scientists Sungsik Lee and Benjamin Reinhart at 12BM of Advanced Photon Source at Argonne National Laboratory, supported by the U.S. Department of Energy, Basic Energy Science, under Contract No. DE-AC02-06CH11357. The authors also acknowledge beamline BL14W1 of the Shanghai Synchrotron Radiation Facility (SSRF).
© The Royal Society of Chemistry.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)