The use of anion redox reactions is gaining interest for increasing rechargeable capacities in alkaline ion batteries. Although anion redox coupling of S2− and (S2)2− through dimerization of S–S in sulfides have been studied and reported, an anion redox process through electron hole formation has not been investigated to the best of our knowledge. Here, we report an O3-NaCr2/3Ti1/3S2 cathode that delivers a high reversible capacity of ~186 mAh g−1 (0.95 Na) based on the cation and anion redox process. Various charge compensation mechanisms of the sulfur anionic redox process in layered NaCr2/3Ti1/3S2, which occur through the formation of disulfide-like species, the precipitation of elemental sulfur, S–S dimerization, and especially through the formation of electron holes, are investigated. Direct structural evidence for formation of electron holes and (S2)n− species with shortened S–S distances is obtained. These results provide valuable information for the development of materials based on the anionic redox reaction.
|Publication status||Published - 2019 Dec 1|
Bibliographical noteFunding Information:
This work was financially supported by the National Natural Science Foundation of China (Grant No. 21773037, 21473235, 11227902, 11704245 and U1632269); the National Key Scientific Research Project (Grant No. 2016YFB090150); Shanghai Pujiang Program (17PJ1403700). The work at Taiwan Light Source (beamline 16A1) was supported by National Synchrotron Radiation Research Center. The work at Brookhaven National Laboratory was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technology Office of the U.S. Department of Energy through the Advanced Battery Materials Research (BMR) Program, including Battery500 Consortium under contract DE-SC0012704. This research used resources at beamlines 7-BM (QAS), 8-BM (TES) of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract no. DE-SC0012704. DFT calculation was performed in National Supercomputing Center in Shenzhen (Shenzhen Cloud Computing Center). P.L. is supported by the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning. The authors also thank beamline BL14B1 of the Shanghai Synchrotron Radiation Facility (SSRF). G.-X.R. also acknowledges the support from the UCAS Joint Ph.D. Training Program. The authors gratefully acknowledge the help by Prof. Xi-Qian Yu for his help on in situ XRD measurements, Bo-Yuan Ning, and Hong-Kun Zhu at Fudan University for their help on DFT calculations, Peng-Fei Yu, Xin-Yang Yue, Qin-Chao Wang, Ding-Ren Shi, Jing-Ke Meng, Wei-Wen Wang, Si-Yu Yang and He-Yi Xia for their help on experiments.
© 2019, The Author(s).
All Science Journal Classification (ASJC) codes
- Biochemistry, Genetics and Molecular Biology(all)
- Physics and Astronomy(all)