Optical and electrochemical properties of Li+ intercalated Zr–Ce oxide and Hf–Ce oxide films

• Published in: Journal of applied physics 1998-02, Vol.83 (3), p.1670-1676
• Main Authors: Veszelei, M., Kullman, L., Stro/mme Mattsson, M., Azens, A., Granqvist, C. G.
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550; 1089-7550
• DOI: 10.1063/1.366883

Sputter deposited Zr–Ce oxide and Hf–Ce oxide films were investigated with regard to structure, optical absorption, and electrochemical properties. X-ray diffractometry and Rutherford backscattering spectrometry showed that polycrystalline Zr–Ce oxide and Hf–Ce oxide films had cubic crystal structures for 40–100 mol % CeO2 and 50–100 mol % CeO2, respectively. Cyclic voltammetry was performed in an electrolyte of propylene carbonate containing LiClO4. The charge capacity was ∼60 mC/cm2μm for a Zr–Ce oxide film with a Ce/Zr atom ratio of ∼13 as well as for a Hf–Ce oxide film with a Ce/Hf atom ratio of ∼2. A decrease of the charge capacity was noted after ∼1000 voltammetric cycles, with the mixed oxide films being far more stable than CeO2. In situ optical transmittance measurements showed that both Zr–Ce and Hf–Ce oxide films remained essentially transparent during Li+ intercalation. Chronopotentiometry measurements were used to elucidate effects of the electronic structure during Li+ intercalation.