Effect of Ar+ irradiation on the electrical conductivity of BaCe0.9Y0.1O3−δ

► We suggest a background for method to improve the electrical conductivity using surface modification. ► Increasing the fluence of Ar+ ion beam increases the number of oxygen vacancy. ► With increased fluence, the hydrogen concentration increased due to the increase in the number of oxygen vacancies, which contributed the formation of proton defects. ► Surface modification results in increase of conductivity.