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Nano Lett. 2016 Apr 13;16(4):2663-73. doi: 10.1021/acs.nanolett.6b00318. Epub 2016 Mar 31.

Insight into the Capacity Fading Mechanism of Amorphous Se2S5 Confined in Micro/Mesoporous Carbon Matrix in Ether-Based Electrolytes.

Nano letters

Gui-Liang Xu, Tianyuan Ma, Cheng-Jun Sun, Chao Luo, Lei Cheng, Yang Ren, Steve M Heald, Chunsheng Wang, Larry Curtiss, Jianguo Wen, Dean J Miller, Tao Li, Xiaobing Zuo, Valeri Petkov, Zonghai Chen, Khalil Amine

Affiliations

  1. Chemical Sciences and Engineering Division, Argonne National Laboratory , Lemont, Illinois 60439, United States.
  2. Materials Science Program, University of Rochester , Rochester, New York 14627, United States.
  3. X-ray Science Division, Argonne National Laboratory , Lemont, Illinois 60439, United States.
  4. Department of Chemical and Biomolecular Engineering, University of Maryland , College Park, Maryland 20742, United States.
  5. Materials Science Division, Argonne National Laboratory , Lemont, Illinois 60439, United States.
  6. Center for Nanoscale Materials, Nanoscience Technology, Argonne National Laboratory , Lemont, Illinois 60439, United States.
  7. Department of Physics, Central Michigan University , Mt. Pleasant, Michigan 48859, United States.

PMID: 27022761 DOI: 10.1021/acs.nanolett.6b00318

Abstract

In contrast to the stable cycle performance of space confined Se-based cathodes for lithium batteries in carbonate-based electrolytes, their common capacity fading in ether-based electrolytes has been paid less attention and not yet well-addressed so far. In this work, the lithiation/delithiation of amorphous Se2S5 confined in micro/mesoporous carbon (Se2S5/MPC) cathode was investigated by in situ X-ray near edge absorption spectroscopy (XANES) and theoretical calculations. The Se2S5/MPC composite was synthesized by a modified vaporization-condensation method to ensure a good encapsulation of Se2S5 into the pores of MPC host. In situ XANES results illustrated that the lithiation/delithiation reversibility of Se component was gradually decreased in ether-based electrolytes, leading to an aggravated formation of long-chain polyselenides during cycling and further capacity decay. Moreover, ab initio calculations revealed that the binding energy of polyselenides (Li2Sen) with carbon host is in an order of Li2Se6 > Li2Se4 > Li2Se. The insights into the failure mechanism of Se-based cathode gain in this work are expected to serve as a guide for future design on high performance Se-based cathodes.

Keywords: Se2S5/MPC cathode; ab initio calculations; batteries; capacity fading; ether-based electrolytes; in situ XANES

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