Investigation of Ionic Behavior of Boron Doped Ceria Oxide Ion Conductors using Electrochemical Techniques

Abstract

In this study, Boron Doped Ceria (BDC) ionic conductor is prepared by co-precipitation method. Three different samples with different concentrations of boric acid and cerium nitrate were synthesized with ratio B0.3Ce0.70, B0.20Ce0.80 and B0.10Ce0.90 named as BDC-1, BDC-2 and BDC-3 respectively. Sodium carbonate was used as precipitating agent in quantity 20% of total sample. Then fabricated electrolyte was sintered at the temperature 700 ℃ in the furnace. Raman analysis of the electrolyte was conducted to evaluate the vibrational and rotational modes of material. The intense peak showed the vibrational mode of cerium oxide and lower peak showed an oxygen vacancy over some range of 550-650 cm -1 . These results showed that BDC electrolyte have high oxygen vacancies with the increase in sintering temperature. FTIR results showed the formation of the Ce- O bonds, OH stretching, metal-oxide bonds and some residual material peaks. Furthermore, FTIR spectra of the ionic conductor revealed OH stretching indicating that moisture is present in the sample. The conductivity measurements showed that conductivity of BDC-2 was electrolyte 0.086 Scm -1 at 750 ℃. These results revealed that the BDC electrolyte shows high ionic conductivity at intermediate temperatures that makes it useful for SOFC application. Fuel cell performance for BDC electrolyte materials was analyzed by using BCFZ anode and LSCZ cathode and a plot of voltage was drawn. BDC-2 having medium amount of doped Boron achieved high OCV as compared to BDC-1 and BDC-3. It was observed that cerium is best conductor so, its conductive behavior elevates the OCV as compared to Gd and Sm.