Investigation of Solid Electrolyte Interphase Formed on Si Nanoparticle Composite Electrodes Using Hyperpolarized 129Xe Nuclear Magnetic Resonance Spectroscopy

Mao, Yougang; Karan, Naba K.; Song, Myeonghun; Hopson, Russell; Guduru, Pradeep R.; Wang, Li-Qiong

doi:10.1021/acs.energyfuels.7b00250

Title: Investigation of Solid Electrolyte Interphase Formed on Si Nanoparticle Composite Electrodes Using Hyperpolarized ¹²⁹Xe Nuclear Magnetic Resonance Spectroscopy

Journal Article · Mon Apr 03 00:00:00 EDT 2017 · Energy and Fuels

DOI:https://doi.org/10.1021/acs.energyfuels.7b00250· OSTI ID:1534483

Mao, Yougang ^[1]; Karan, Naba K. ^[1]; Song, Myeonghun ^[1]; Hopson, Russell ^[1]; Guduru, Pradeep R. ^[1];

^[1]

Brown Univ., Providence, RI (United States)

Solid electrolyte interphase (SEI) plays an important role in determining electrochemical performances of Li-ion batteries. The ideal SEI layer protects the electrolyte from being further reduced on the electrode surface and allows Li-ion diffusion in and out of electrodes without any consumption. However, degradation of the SEI layer over time, which contributes to the thickening of the SEI layer, is a leading pathway for gradual capacity fade. In this study, a hyperpolarized (HP) ¹²⁹Xe nuclear magnetic resonance (NMR) technique was applied for the first time to probe changes in porosity and connectivity in Si nanoparticle composite electrodes as a result of the SEI formation. Nanopores are present in nanocomposite electrodes as a result of aggregation of the constituting nanoparticles. The connectivity among nanopores greatly affects the ion transport property of the electrode materials, which has a substantial influence on the overall energy output of Li-ion batteries. Here, information on thickness, uniformity of the SEI layer, and connectivity of the pores in the composite electrodes upon growing SEI was obtained from the analysis of temperature-dependent HP ¹²⁹Xe NMR spectra. Such information is useful for gaining a better understanding of the degradation mechanism of SEI. This study demonstrates that HP ¹²⁹Xe NMR is a potentially unique tool in probing the porosity and connectivity changes in porous practical electrodes during electrochemical cycling.

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