In the present investigation, LiNbO3 dispersed Li2CO3 composite of varying volume fraction is prepared. Its validity of placement in ionic conductor is verified by determining ionic transference number by Wagner’s dc polarization technique and bulk electrical conductivity is estimated with complex impedance spectroscopy. Two different conduction mechanisms are revealed by the complex impedance plots at low and high frequencies. Significant enhancement in the ionic conductivity has resulted due to enhancement in vacancies at the grain boundary interface facilitated by the localized polarization of carbonate grains due to the presence of ferroelectric phase. The effect on electrode kinetics is studied by characterizing an electrochemical CO2 gas sensor with this composite as sensing electrode which showed significant reduction in response time and recovery time (<10 sec). The use of such composite systems will benefit the development of fast electrochemical devices.