Preparation and transport properties of Li-doped NiO and (Li + Ca)-doped NiO oxides

The transport properties of Li-doped NiO and (Li + Ca)-doped NiO were investigated in the high temperature region up to 1073 K. All the oxide samples were prepared by a sol-gel method followed by a sintering procedure. The wet-chemical processing is efficient to prepare oxide ceramics due to shortening of the overall preparation time period. The electrical conductivity and Seebeck coefficients of the samples were measured from 300 to 1073 K. A semiconductor-metal transition was observed in the samples. The Li and Ca dopants have a remarkable effect on the transport properties of the oxides.