skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The Effect of Pre-Analysis Washing on the Surface Film of Graphite Electrodes

Authors:
; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V)
OSTI Identifier:
1315842
Grant/Contract Number:
AC02-06CH11357
Resource Type:
Journal Article: Published Article
Journal Name:
Electrochimica Acta
Additional Journal Information:
Journal Volume: 206; Journal Issue: C; Related Information: CHORUS Timestamp: 2016-09-14 02:24:05; Journal ID: ISSN 0013-4686
Publisher:
Elsevier
Country of Publication:
United Kingdom
Language:
English

Citation Formats

Somerville, L., Bareño, J., Jennings, P., McGordon, A., Lyness, C., and Bloom, I. The Effect of Pre-Analysis Washing on the Surface Film of Graphite Electrodes. United Kingdom: N. p., 2016. Web. doi:10.1016/j.electacta.2016.04.133.
Somerville, L., Bareño, J., Jennings, P., McGordon, A., Lyness, C., & Bloom, I. The Effect of Pre-Analysis Washing on the Surface Film of Graphite Electrodes. United Kingdom. doi:10.1016/j.electacta.2016.04.133.
Somerville, L., Bareño, J., Jennings, P., McGordon, A., Lyness, C., and Bloom, I. 2016. "The Effect of Pre-Analysis Washing on the Surface Film of Graphite Electrodes". United Kingdom. doi:10.1016/j.electacta.2016.04.133.
@article{osti_1315842,
title = {The Effect of Pre-Analysis Washing on the Surface Film of Graphite Electrodes},
author = {Somerville, L. and Bareño, J. and Jennings, P. and McGordon, A. and Lyness, C. and Bloom, I.},
abstractNote = {},
doi = {10.1016/j.electacta.2016.04.133},
journal = {Electrochimica Acta},
number = C,
volume = 206,
place = {United Kingdom},
year = 2016,
month = 7
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.electacta.2016.04.133

Citation Metrics:
Cited by: 1work
Citation information provided by
Web of Science

Save / Share:
  • The electrochemical performance of cells with a Li 1.03(Ni 0.5Co 0.2Mn 0.3) 0.97O 2 (NCM523) positive electrode and a blended silicon-graphite (Si-Gr) negative electrode are investigated using various electrolyte compositions and voltage cycling windows. Voltage profiles of the blended Si-Gr electrode show a superposition of graphite potential plateaus on a sloped Si profile with a large potential hysteresis. The effect of this hysteresis is seen in the cell impedance versus voltage data, which are distinctly different for the charge and discharge cycles. We confirm that the addition of compounds, such as vinylene carbonate (VC) and fluoroethylene carbonate (FEC) to themore » baseline 1.2 M LiPF 6 in ethylene carbonate (EC): ethyl methyl carbonate (EMC) (3:7 w/w) electrolyte, improves cell capacity retention with higher retention seen at higher additive contents. We show that reducing the lower cutoff voltage (LCV) of full cells to 2.5 V increases the Si-Gr electrode potential to 1.12 V vs. Li/Li +; this relatively-high delithiation potential correlates with the lower capacity retention displayed by the cell. Hence, we show that raising the upper cutoff voltage (UCV) can increase cell energy density without significantly altering capacity retention over 100 charge discharge cycles.« less
  • The effect of mechanical milling on powder mixtures consisting of graphite and AB{sub 5} alloys, prepared either by mechanical alloying or by a high-temperature melting process, has been investigated. The resulting hydride-forming composite electrodes show a 10 and 40% capacity enhancement for arc-melted and mechanically prepared AB{sub 5} alloys, respectively. Such an increase in capacity is suggested to be the result of several cumulative effects: (1) a mechanically induced reducing role of graphite which eliminates the AB{sub 5} particles of oxide coatings, enabling a better hydrogen adsorption/absorption and diffusion into the insertion sites of the alloy, (2) the appearance ofmore » an increasingly important double-layer capacitance on each particle with increased milling time that adds to the faradic component, and (3) the improved electronic conductivity between the active AB{sub 5} material and the graphite that allows a better utilization of the alloy.« less
  • Lithium malonate (LM) was coated on the surface of a natural graphite (NG) electrode, which was then tested as the negative electrode in the electrolytes of 0.9 M LiPF6/EC-PC-DMC (1/1/3, by weight) and 1.0 M LiBF4/EC-PC-DMC (1/1/3, by weight) under a current density of 0.075 mA cm-2. LM was also used as an additive to the electrolyte of 1.0 M LiPF6/EC-DMC-DEC (1/1/1, by volume) and tested on a bare graphite electrode. It was found that both the surface coating and the additive approach were effective in improving first charge discharge capacity and coulomb efficiency. Electrochemical impedance spectra showed that themore » decreased interfacial impedance was coupled with improved coulomb efficiency of the cells using coated graphite electrodes. Cyclic voltammograms (CVs) on fresh bare and coated natural graphite electrodes confirmed that all the improvement in the half-cell performance was due to the suppression of the solvent decomposition through the surface modification with LM. The CV data also showed that the carbonate electrolyte with LM as the additive was not stable against oxidation, which resulted in lower capacity of the full cell with commercial graphite and LiCoO2 electrodes.« less
  • Graphite samples were pressed in an electrically-heated press at a temperature of 106 to 110 deg C at a pressure of 1000 kg/cm/sup 2/. The apparent specific gravity of the sample increased from 1.721 at a residual pressure of 746 mm Hg std to 1.761 at a residual pressure of 10 mm Hg std. Vacuum was then applied to the pressing of graphitic rods 50 mm in diameter and electrodes 75 mm in diameter. A significant increase in density and mechanical strength was observed at a vacuum of approximates 700 mm Hg std. The apparent specific gravity increased from 1.579more » without the use of vacuum to 1.646 at a residual pressure of 40 to 80 mm Hg std during pressure. The mechanical strength in compression increased from 213 to 264 kg/cm/sup 2 for the vacuum-pressed sample. The bending strength increased from 96 to 126 kg/cm/sup 2/, and the rupture strength increased from 49 to 67 kg/cm/sup 2/. The porosity of the graphite decreased from 28.2 to 25.5%. The vacuum-pressed sample resisted oxidation a factor of two better om being heated to 700 deg C for a period of 2 hours. The higher the applied vacuum, the better was the improvement in physical properties. (TTT)« less