Li{sub 9}SiAlO{sub 8}: A lithium ion electrolyte for voltages above 5.4V

Journal Article · Mon Jul 01 04:00:00 EDT 1996 · Journal of the Electrochemical Society

DOI:https://doi.org/10.1149/1.1836980· OSTI ID:367768

Neudecker, B J ^[1]; Weppner, W ^[2]

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1. Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany)
2. Christian-Albrechts-Univ., Kiel (Germany). Technische Fakultaet

The solid solution compound Li{sub 9}SiAlO{sub 8} represents a single-phase Li{sub 4}SiO{sub 4} derivative formally composed of 50 atom percent (a/o) Li{sub 4}SiO{sub 4} and 50 a/o Li{sub 5}AlO{sub 4}. It exhibits an ionic conductivity {sigma}{sub Li{sup +}} = 2.3 {times} 10{sup {minus}7} S/cm at 25 C. The total electronic conductivity in contact with elemental lithium or highly positively polarized electrodes is found to be around four orders of magnitude smaller. Detailed studies under different conditions and in different cell types are presented. In the asymmetric cell type ({minus}) Li{vert_bar}Li{sub 9}SiAlO{sub 8}{vert_bar}Ta (+), the tantalum electrode served as an arbitrary positive electrode simulating different lithium activities due to the applied external voltage. Upon extreme polarization (E vs Li/Li{sup +} {le} 6.5 V) below 100 C, stable tarnishing layers were formed at the Li{sub 9}SiAlO{sub 8}-electrode interfaces, thus resisting further decomposition, which makes Li{sub 9}SiAlO{sub 8} a suitable electrolyte for investigating cathodes which exhibit very high positive voltages vs. lithium. Moreover, chemical stability experiments show this electrolyte to be inert against elemental lithium and Li{sub 0.9}Mn{sub 2}O{sub 4} up to at least 100 and 500 C, respectively. Li{sub 9}SiAlO{sub 8} crystallizes in a monoclinic unit cell having the parameters a = 5.108(4) {angstrom}, b = 5.388(4) {angstrom}, c = 6.205(6) {angstrom}, and {beta} = 90.40(9){degree}.

• Sponsoring Organization: USDOE
• OSTI ID: 367768
• Journal Information: Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 7 Vol. 143; ISSN 0013-4651; ISSN JESOAN
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
36 MATERIALS SCIENCE
ALUMINATES
ALUMINIUM OXIDES
CRYSTAL STRUCTURE
ELECTRIC BATTERIES
ELECTROLYTES
IONIC CONDUCTIVITY
LITHIUM COMPOUNDS
LITHIUM OXIDES
MANGANESE OXIDES
SILICATES
SILICON OXIDES
SOLID SOLUTIONS