Interfacial Disordering and Heterojunction Enabling Fast Proton Conduction

Abstract

Abstract Interfacial disorder is a general method to change the metal-oxygen compatibility and carrier density of heterostructure materials for ionic transport modulation. Herein, to enable high proton conduction, a semiconductor heterostructure based on spinel ZnFe2O4 (ZFO) and fluorite CeO2 is developed and investigated in terms of structural characterization, first principle calculation, and electrochemical performance. Particular attentions are paid to the interfacial disordering and heterojunction effects of the material. Results show that the heterostructure induces a disordered oxygen region at the hetero-interface of ZFO-CeO2 by dislocating oxygen atoms, leading to fast proton transport. As a result, the ZFO-CeO2 exhibits a high proton conductivity of 0.21 S/cm and promising fuel cell power output of 1070 mW/cm2 at 510 ℃. Based upon these findings, a new mechanism is proposed to interpret the diffusion and acceleration of protons in ZFO-CeO2. Our study provides a new strategy to customize semiconductor heterostructure to enable fast proton conduction.