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Author Kanoh, Hirofumi ♦ Feng, Q. ♦ Hirotsu, Takahiro ♦ Ooi, Kenta
Sponsorship USDOE
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword ENERGY STORAGE ♦ ELECTRIC BATTERIES ♦ ELECTRODES ♦ FABRICATION ♦ LITHIUM ♦ DIFFUSION ♦ IMPREGNATION ♦ PLATINUM ♦ MANGANESE OXIDES
Abstract The kinetics of lithium electroinsertion into a Pt/{lambda}-MnO{sub 2} thin-film electrode in a 10 mmol/dm{sup 3} LiCl solution was studied by ac impedance spectroscopy between 10{sup {minus}4} and 10{sup 2} Hz at 25 C. The interfacial charge-transfer process was found to be independent of the composition x in Li{sub x}Mn{sub 2}O{sub 4}, and the exchange current density was 1.3 {times} 10{sup {minus}6} A/cm{sup 2} irrespective of x, whereas the chemical diffusion coefficient, D{sub Li}, and the partial conductivity, {sigma}{sub Li}, of lithium depended greatly on x because of the effect of the thermodynamic enhancement factor, W. The {tilde D}{sub Li} value varied between 1.9 {times} 10{sup {minus}12} and 3.1 {times} 10{sup {minus}11} cm{sup 2}/s, reaching a minimum when x = 0.2 approximately. The {sigma}{sub Li} value was in the range from 2.8 {times} 10{sup {minus}6} to 1.2 {times} 10{sup {minus}5} S/cm. This low {sigma}{sub Li} value indicates the predominant contribution of electronic conductivity to the total conductivity of Li{sub x}Mn{sub 2}O{sub 4}, which is in the order of 10{sup {minus}4} S/cm. The results show that solid-state diffusion of Li{sup +} ions is a rate-determining process in the system. Application is to secondary batteries.
ISSN 00134651
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-08-01
Publisher Place United States
Journal Journal of the Electrochemical Society
Volume Number 143
Issue Number 8


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