Characterization of Thin Film Lithium Electrode Materials

Thin if-sputtered films of Li(4)Fe(0.5 +/- x)Ti(4.5 +/- y)O(11.75 +/- z), Li(4)Co(0.5 +/- x)Ti(4.5 +/- y)O(11.5 +/- z), Li(4)Ti(5 +/- x)O(12 +/- y), LiCo(1 +/- x)O(2 +/- y) and C were investigated by X-ray diffraction, thickness and weight determination, ICP/AAS, EDX and coulometric titration experiments employing the following liquid electrolytes (PC:EC:DMC=1:1:3, 1 M LiPF(6)), (PC:DEC=1:4, 1 M LiPF(6)), (EC:DMC=1: 1, 1 M LiPF(6)), (PC:DME=1:1, 1 M LiClO(4)) and (gamma-buthyrolactone, 1M LiClO(4)). For comparison, cold isostatically pressed monolithic pellets of Li(4)Fe(0.5)Ti(4.5)O(11.75), Li(4)Co(0.5)Ti(4.5)O(11.5) and Li(4)Ti(5)O(12) were examined. The slope of the coulometric titration curves depends strongly on the employed liquid electrolyte. In the case of thin films, the stoichiometric width of the liquid electrolyte salt may have an additional impact on the results.