Mechanism of Exact Transition between Cationic and Anionic Redox Activities in Cathode Material Li2FeSiO4

Zheng, Jiaxin1; Teng, Gaofeng1; Yang, Jinlong1; Xu, Ming1; Yao, Qiushi2,3; Zhuo, Zengqing1,4; Yang, Wanli4; Liu, Qihang2,3; Pan, Feng1

2018-11

10.1021/acs.jpclett.8b02725

Journal of Physical Chemistry Letters   影响因子和分区

1948-7185

The discovery of anion redox activity is promising for boosting the capacity of lithium ion battery (LIB) cathodes. However, fundamental understanding of the mechanisms that trigger the anionic redox is still lacking. Here, using hybrid density functional study combined with experimental soft X-ray absorption spectroscopy (sXAS) measurements, we unambiguously proved that Li((2-x))FeSiO4 performs sequent cationic and anionic redox activity through delithiation. Specifically, Fe2+ is oxidized to Fe3+ during the first Li ion extraction per formula unit (f.u.), while the second Li ion extraction triggered the oxygen redox exclusively. Cationic and anionic redox result in electron and hole polaron states, respectively, explaining the poor conductivity of Li((2-x))FeSiO4 noted by previous experiments. In contrast, other cathode materials in this family exhibit diversity of the redox process. Li2MnSiO4 shows double cationic redox (Mn2+-Mn4+) during the whole delithiation, while Li2CoSiO4 shows simultaneous cationic and anionic redox. The present finding not only provides new insights into the oxygen redox activity in polyanionic compounds for rechargeable batteries but also sheds light on the future design of high-capacity rechargeable batteries.

SCI ; EI

英语

NI期刊

通讯

Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy[DE-AC02-05CH11231]

Chemistry ; Science & Technology - Other Topics ; Materials Science ; Physics

Chemistry, Physical ; Nanoscience & Nanotechnology ; Materials Science, Multidisciplinary ; Physics, Atomic, Molecular & Chemical

WOS:000449308200015

AMER CHEMICAL SOC

20184305991895

Cathodes ; Cobalt compounds ; Extraction ; Ions ; Lithium ; Lithium compounds ; Manganese compounds ; Redox reactions ; Silicon compounds ; X ray absorption spectroscopy ; X rays

Lithium and Alloys:542.4 ; Chemical Reactions:802.2 ; Chemical Operations:802.3 ; Atomic and Molecular Physics:931.3 ; High Energy Physics:932.1

Web of Science

1.Peking Univ, Sch Adv Mat, Shenzhen Grad Sch, Shenzhen 518055, Peoples R China
2.Southern Univ Sci & Technol, Shenzhen Inst Quantum Sci & Engn, Shenzhen 518055, Peoples R China
3.Southern Univ Sci & Technol, Dept Phys, Shenzhen 518055, Peoples R China
4.Lawrence Berkeley Natl Lab, Adv Light Source, Berkeley, CA 94720 USA

Zheng, Jiaxin,Teng, Gaofeng,Yang, Jinlong,et al. Mechanism of Exact Transition between Cationic and Anionic Redox Activities in Cathode Material Li2FeSiO4[J]. Journal of Physical Chemistry Letters,2018,9(21):6262-6268.

Zheng, Jiaxin.,Teng, Gaofeng.,Yang, Jinlong.,Xu, Ming.,Yao, Qiushi.,...&Pan, Feng.(2018).Mechanism of Exact Transition between Cationic and Anionic Redox Activities in Cathode Material Li2FeSiO4.Journal of Physical Chemistry Letters,9(21),6262-6268.

Zheng, Jiaxin,et al."Mechanism of Exact Transition between Cationic and Anionic Redox Activities in Cathode Material Li2FeSiO4".Journal of Physical Chemistry Letters 9.21(2018):6262-6268.