New Approach to Improve Ionic Conductivity at Low Temperature by the Decomposition of KHCO 3 in the Nanocomposite Electrolyte C e 0 . 7 L a 0 . 15 C a 0 . 15 O 2 - δ @ K H C O 3

The current work principally treats the significant aspects of solid electrolytes based on cerium oxide in the absence and presence of potassium bicarbonate. The classic oxide electrolyteC e 0 . 7L a 0 . 15C a 0 . 15O 2 - δ(LCDC) and the bicarbonate nanocomposite electrolyteC e 0 . 7L a 0 . 15C a 0 . 15O 2 - δ@KHC O 3 (LCDC@KHC) are synthesized separately via self‐combustion and co‐precipitation techniques. Structural, thermal, electro‐morphological and electrochemical properties of pure LCDC and nanocomposite material LCDC@KHC are carefully examined. In particular, the influence of the heavily coupling amongst LCDC oxide and KHCO 3 bicarbonate on the microstructures and ionic conductivities of KHCO 3 ‐coated nanocrystalline LCDC is studied by TG/DTA, Raman, FEGSEM and AC impedance spectroscopy. Thermal analyses show that the LCDC@KHC nacomposite is stable at a temperature below 122 °C. Beyond this temperature, the LCDC@KHC O 3 nanocomposite is transformed into a LCDC@ K H C O 3/ K 2C O 3nanocomposite. XRD data confirms that the LCDC phase and the various nanocomposite materials LCDC@KHC, sintering at different temperatures, adopt the fluorite structure. Lattice parameters and bond lengths are determined by Rietveld refinement. The ionic conductivity of bicarbonate nanocomposite electrolyte LCDC@KHC is 100 to 1000 times higher than that of the novel classic electrolyte LCDC. The remarkable enhancement of conductivity as a function of temperature rise is correlated to the presence of potassium in two forms: bicarbonate and carbonate in the LCDC@ K H C O 3/ K 2C O 3nanocomposite electrolyte.