OPTICAL AND ELECTROCHEMICAL PROPERTIES OF LI-CE OXIDE AND HF-CE OXIDE-FILMS( INTERCALATED ZR)

Sputter deposited Zr-Ce oxide and Hf-Ce oxide films were investigated with regard to structure, optical absorption, and electrochemical prop erties. X-ray diffractometry and Rutherford backscattering spectrometr y showed that polycrystalline Zr-Ce oxide and Hf-Ce oxide films had cu bic crystal structures for 40-100 mol% CeO2 and 50-100 mol % CeO2, res pectively. Cyclic voltammetry was performed in an electrolyte of propy lene carbonate containing LiClO4. The charge capacity was similar to 6 0 mC/cm(2) mu m for a Zr-Ce oxide film with a Ce/Zr atom ratio of simi lar to 13 as well as for a Hf-Ce oxide film with a Ce/Hf atom ratio of similar to 2. A decrease of the charge capacity was noted after simil ar to 1000 voltammetric cycles, with the mixed oxide films being far m ore stable than CeO2. In situ Optical transmittance measurements showe d that both Zr-Ce and Kf-Ce oxide films remained essentially transpare nt during Li+ intercalation. Chronopotentiometry measurements were use d to elucidate effects of the electronic structure during Li+ intercal ation. (C) 1998 American Institute of Physics. [S0021-8979(98)08303-0] .