期刊
NANO LETTERS
卷 16, 期 4, 页码 2663-2673出版社
AMER CHEMICAL SOC
DOI: 10.1021/acs.nanolett.6b00318
关键词
Se2S5/MPC cathode; batteries; capacity fading; ether-based electrolytes; in situ XANES; ab initio calculations
类别
资金
- U.S. Department of Energy, Vehicle Technologies Office
- U.S. DOE [DE-AC02-06CH11357]
- US Department of Energy Basic Energy Sciences
- Canadian Light Source
- University of Washington
- Advanced Photon Source
- DOE-BES [DE-SC0006877]
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.
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