Abstract:
Zinc oxide based thin films have been grown on glass and stainless steel substrates in two steps; thermal evaporation from high purity metallic zinc and D.C. plasma oxidation. X-ray diffraction has shown that the films were polycrystalline nature and small predominant orientation at some specific planes. Analysis showed that plasma oxidation starts from the thermally evaporated leaf-like surfaces and produces a core shell structure of ZnO on the metallic Zn. Increasing plasma oxidation power causes increased amount of ZnO volume and resistivity. Coin-type (CR2016) test cells were assembled in an argon-filled glove box and cyclically tested. The electrochemical performance of the films has been studied by cyclic voltammetry. The dependence of converted Li-ions on voltage profile of the films has been determined. It was found that the Zn/ZnO films exhibited highest the number of converted Li-ions at 175 W plasma oxidation conditions. Discharge capacity measurements revealed the double phase structures of Zn/ZnO exhibited significantly high reversible capacities. The high capacity and low capacity fade values were attributed to the high electrical conductivity and buffering ability of metallic Zn in the anodes.
