Theoretical and experimental study on a fast proton transport pathway in CeO2-coated SrTiO3-δ through surface vacancy engineering for low-temperature ceramic fuel cells

Sajid Rauf; Zuhra Tayyab; Mak Yousaf Shah; Abdullah Tahir; Muhammad Shahid Sharif; Dmitry Medvedev; Nawal K Almaymoni; Yibin Tian

doi:10.1016/j.jcis.2025.138871

Theoretical and experimental study on a fast proton transport pathway in CeO₂-coated SrTiO_3-δ through surface vacancy engineering for low-temperature ceramic fuel cells

J Colloid Interface Sci. 2026 Jan 15;702(Pt 1):138871. doi: 10.1016/j.jcis.2025.138871. Epub 2025 Aug 29.

Authors

Sajid Rauf¹, Zuhra Tayyab¹, Mak Yousaf Shah¹, Abdullah Tahir², Muhammad Shahid Sharif³, Dmitry Medvedev⁴, Nawal K Almaymoni⁵, Yibin Tian⁶

Affiliations

¹ College of Mechatronics and Control Engineering & State Key Lab of Radio Frequency Heterogenous Integration, Shenzhen University, Shenzhen 518060, China.
² Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong, China.
³ School of Energy and Environment, Southeast University, Nanjing 210096, China.
⁴ Hydrogen Energy Laboratory, Ural Federal University, Ekaterinburg 620002, Russia; Laboratory of Electrochemical Devices Based on Solid Oxide Proton Electrolytes, Institute of High Temperature Electrochemistry, Ekaterinburg 620066, Russia.
⁵ Department of Physics, College of Science, Princess Nourah Bint Abdulrahman University, Riyadh 11671, Saudi Arabia.
⁶ College of Mechatronics and Control Engineering & State Key Lab of Radio Frequency Heterogenous Integration, Shenzhen University, Shenzhen 518060, China. Electronic address: ybtian@szu.edu.cn.

PMID: 40902482
DOI: 10.1016/j.jcis.2025.138871

Abstract

Overcoming the high-temperature limitations of ceramic fuel cells (CFCs) requires the development of electrolytes capable of efficient proton transport at reduced operating temperatures. In this work, we introduced a surface-engineered SrTiO_3-δ electrolyte coated with 10 mol%-CeO₂, forming a core-shell heterostructure that promoted the formation of oxygen vacancies localized at the interface. These vacancies significantly reduced the energy barrier for proton migration, enabling enhanced ionic conductivity at low operating temperatures. The 10 mol%-CeO₂-coated SrTiO_3-δ exhibited a high ionic conductivity of 0.14 S cm^-1 and delivered a peak power density of 0.81 W cm^-2 at 550 °C. Isotopic substitution and proton-blocking membrane experiments confirmed a dominant protonic conduction mechanism, contributing up to 78 % of the total power-output. Density functional theory calculations revealed that the CeO₂ coating layer lowered the oxygen vacancy formation energy to 3.7 eV and facilitated charge redistribution favorable to proton transport. This work established a scalable and cost-effective surface modification strategy to realize high-performance electrolytes for low-temperature CFCs, surpassing conventional bulk doping approaches in both conductivity and electrochemical output.

Keywords: Ceramic FCs (CFCs); Core-shell structure; Density functional theory (DFT); High proton conductivity; Perovskite matrix; Surface coating.