Lithium Ionic Conductivity of Some Lithium Iodoles
- PDF / 442,397 Bytes
- 8 Pages / 420.48 x 639 pts Page_size
- 14 Downloads / 278 Views
Lithium Ionic Conductivity of Some Lithium Iodoles Michael D. Lewis Department of Chemistry, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08855--0939 ABSTRACT The search for lithium ion conductors in crystalline or polycrystalline solid state ionic materials has resulted in finding a new class of compounds. Five new, stable, homogeneous compounds formed in the lithium alcohol systems, LiI-(ROH)x for R=CH3 CH 2OH, CH 3CH2 CH 2 OH, CH 3 CHOHCH 3 , and CH 3OH have been identified and characterized.
INTRODUCTION Lithium ion conductivity in the solid state is a subject of great interest in electrochemical battery technology. Materials with high energy density or high power density and suitable for use as solid electrolytes for room temperature applications have proven difficult to find Some of the more important discoveries in finding solid state ionic conductors have been made with non-lithium ion compounds (Figure 1).
Brief History of Solid State Ionic Conductors YEAR
SCIENTIST(S)
COMPOUND
1839 1884 1899 1914 1921 1940's 1967 1976 1986
Faraday E.Warburg W.Nernst Tubandt and Lorenz Benrath and Drekopf Y.Haven Yao and Kummer Boukamnp and Huggins Weppner and Rabenau
PbF3 Na through glass Mixed Oxides, High T a--AgI, Urag -- 2.0 S/cm LiS0 4 Li Halides, o~jj, 25c -=10-11 S/cm
Li--(t-A1 2 0 3 , Ohli, 25c m 3x10"3 (ohm--cm)-' Li3 N, O'li, 25c =3x10"4 S/cm Li(CH3 OH) 41, £'li+, 25c =--3X10"s S/cm
Figure 1 In this paper• compounds beyond the newly discovered lithium iodide-methanols and single phase, Li (CH 3 OH) 41 are reported [1]. Lithium iodide-alcohol stable phases, also known as lithium iodoles (iodide +{ alcohol = iodole), have been found for LiI-- ROH)x, R= CH 3 CH 2 OH, CH 3CH 2 CH 2 OH and CH 3 CHOHCH3 . The following compounds form: Li (CH 3 CH 2OH )41, Li(CH 3 CHR.CH2 OH)2 I, Li(CHsCH 2 CH 2OH) 4I,Li(CH 3 CHOHCH 3) 2 I, and .Li (CHsCHOHCH3 ) 41. Thermodynamic phase diagrams have been obtained by differential scanning calorimetry (DSC). Optical techniques and low, room and near room temperature xray crystallographic methods for air-sensitive powder and crystalline materials more fully characterize the phases. Lithium ion conductivity was found by impedance spectroscopy, complex nonlinear least squares analysis and three dimensional graphics.
Mat. Res. Soc. Symp. Proc. Vol. 210. 01991 Materials Research Society
694
EXPERIMENTAL Sample preparations were made from pure LiI(99.999%, Aesar) with H 20 < 10 ppm ultra-dry) and high purity reagents ( 99% ) of ethanol, n-propanol and iso-propanol old Label, Aldrich), stored under argon or nitrogen atmospheres. The samples were prepared in stoichiometric quantity (Figure 2) from finely ground lithium iodide and alcohol reagent. All reactions were done under helium atmosphere in a Vacuum Atmosphere dry box (Model M040-1). For thermal analysis measurements, differential scanning calorimetry (DSC) proved most effective. The sample holder for DSC measurement (opaque, coated aluminum) was hermetically sealed under N10,000 lbs/in 2 pressure. A DuP
Data Loading...
