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The use of ceramic semiconductors to serve as an efficient proton conductor is an evolving approach in the novel emerging field of semiconductor protonic fuel cells (SPFCs). One of the most critical challenges in SPFCs is to design a sufficient proton-conductivity of 0.1 S cm−1 below <600 °C. Here we report to tune the perovskite BaSnO 3 (BSO), a semiconductor single-phase material, to be applied as a proton-conducting electrolyte for SPFC. It was found that the oxygen vacancies play a vital role to promote proton transport while the electronic short-circuiting issue of BSO semiconductor has been justified by the Schottky junction mechanism at the anode/electrolyte interface. We have demonstrated a SPFC device to deliver a maximum power density of 843 mW cm−2 with an ionic conductivity of 0.23 S cm−1 for BSO at 550 °C. The oxygen vacancy formation by increasing the annealing temperature helps to understand the proton transport mechanism in BSO and such novel low-temperature SPFC (LT-SPFC). [Display omitted] • Semiconductor BaSnO 3 tuned to be a proton conductor. • Single-phase semiconductor BaSnO 3 developed as the functional electrolyte for SPFC. • BaSnO 3 reached a high proton conductivity of 0.23 S cm−1 at 550 °C. • BaSnO 3 electrolyte fuel cell has shown high-power output of 843 mW cm−2 at 550 °C. [ABSTRACT FROM AUTHOR]

Semiconductor ionic materials (SIM) have recently gained broad attention due to their unique structural and chemical properties that enable efficient proton transport, making them promising materials for advanced fuel cell applications. This mini-review provides an overview of the proton transport phenomena in SIM and discusses their significance and future perspectives. We discuss the different types of SIMs, their proton transport mechanisms, and the factors that affect their performance. Furthermore, we emphasize the correlation between traditional perovskite oxides and SIMs and how this can be leveraged to improve the development of more advanced proton conductors for fuel cells. Also, we have highlighted the Proton-coupled electron transfer (PCET) mechanism in SIM. This mini-review provides a comprehensive overview of the current state of this emerging field, including its scientific foundations, future prospects, and applicable materials, technologies, devices, and basics for proton ceramic fuel cells (PCFCs). • This review covers efficient proton transport in SIM for fuel cell applications. • Discussed SIM protons transport's relevance, prospects, and factors. • To develop fuel cell proton conductors, we study Perovskite-SIM interactions. • This review covers PCET methods, challenges, and SIM's future. [ABSTRACT FROM AUTHOR]

Nowadays, semiconductor ionic materials have drawn significant attention for developing new electrolytes in low temperature solid oxide fuel cells (LT-SOFCs). Here we investigate the effect of nickel doping on ionic conductivity of Sm 2 O 3 as an electrolyte material for low temperature SOFCs. The amount of Ni ion doping has an intense effect on the electrochemical properties and power generation. An optimized composition of 10 mol% nickel doped samarium oxide (10NSO) as an electrolyte in the fuel cell has a high open circuit voltage (OCV) of 1.09 V and a notable power output of 1080 mW cm−2 at 520 °C. Further investigation revealed that the 10NSO displays a superior ionic conduction up to 0.26 S cm−1 at 520 °C. Moreover, the cell demonstrates high stability up to 80 h. The high electrochemical property and good stability recommend that the NSO is a favorable candidate for symmetrical SOFC electrolyte. • Insulating Sm 2 O 3 doped with NiO was developed as a novel electrolyte in LT-SOFC. • Proton conduction was discovered in the NiO-Sm 2 O 3 system. • Ionic conductivity of Ni-doped Sm 2 O 3 could reach to 0.26 S cm−1 at 520 °C. • 10 mol% Ni-doped Sm 2 O 3 achieved a maximum power density of 1080 mW cm−2 at 520 °C. [ABSTRACT FROM AUTHOR]

[Display omitted] • The SFT electrolyte powder synthesized using the co-precipitation technique. • The SFT shows 650 mW/cm2 and 1.14 A/cm2 at 520 °C in fuel cell and electrolysis mode. • Core-shell interface accelerates proton transport. • Band alignment, surface layer, and DRT analysis aid ion and protons transport. In recent years, energy carriers for renewable sources and devices that convert chemical energy into electrical energy, such as solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs), have made hydrogen production economically viable and have numerous industrial uses. We have designed SrFe 0.3 TiO 3 (SFT) materials to function as SOFC and H-SOEC electrolytes at low operational temperatures of 520–420 °C. The SFT (600 °C) shows a higher fuel cell power density of 650 mW/cm2 and a reasonable current density of 1.14 A/cm2 in fuel cell and electrolysis cell mode at 520 °C. The formation of the surface layer enables high ionic and Proton conduction due to a high number of oxygen vacancies, and the core–shell type interface enables easy and quick proton transportation restricted to the surface. Energy band alignment and distribution relaxation time (DRT) were also evaluated to study ion transport in SFT materials. These results open up advanced avenues for the design of high-performance, sophisticated proton-conducting electrolytes for ceramic electrochemical cells. [ABSTRACT FROM AUTHOR]

As an electrolyte, enough ionic conductivity, either proton (H+) or oxide (O2−) conduction, has demanded the better performance of low-temperature (especially below 550 °C) solid oxide fuel cell (LT-SOFCs). Notably, that either conductivity, higher performance, reliability, or higher cost is hampering the LT-SOFC marketing. In our current subject, we report the La-doped BZY proton conductor as an electrolyte has exhibited high ionic conductivity of 0.15 S/cm with a higher performance of 0.78 W/cm2 at 550 °C. Also, the performance of LBZY is superior to the un-doped BZY electrolyte. Such high performance mainly ascribed due to the doping of La into BZY. Besides, the mechanism for high ion conductivity is explained. This work manifests that using the LBZY semiconductor perovskite as an electrolyte is more suitable for fuel cell technology. Image 1 • The La-doped BZY (La-BZY) perovskite was synthesized using the sol-gel method. • La-BZY was applied as an electrolyte material for low-temperature solid oxide fuel cells (LT-SOFCs). • The device contains (La-BZY) electrolyte has delivered the maximum power output 0.78 W/cm2 with high OCV 1.04 V. • A lower value of ohmic resistance and grain boundary resistance may provide the fast ions transport path. • The La-doped BZY has verified to possess the dominant proton (H+) conduction. [ABSTRACT FROM AUTHOR]

Designing a cathode with exceptional oxygen reduction reaction (ORR) activity and durability at intermediate-to-low temperatures is vital to increase the improvement of solid oxide fuel cells (SOFCs), a captivating energy conversion technology with reduced environmental impact and high performance. Cathodes made of perovskite oxides have been developed extensively. Doping is a crucial method for modifying perovskites' lattice diffusion and surface exchange properties to achieve desired catalytic performances in a wide range of redox reactions, including oxygen reduction reactions (ORRs) for ceramic fuel cells (CFCs). The reported BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ (BCFZY) is a potential cathode in CFCs. Here, we systematically explore the partial doping of B-sites with Al of varied content (from 5% to 30%) to further enhance the performance of BCFZY at lower temperatures. The polarization impedance of proton ion conducting fuel cells is lowest in Ba(Co 0.4 Fe 0.4 Zr 0.1 Y 0.1) 0.90 Al 0.1 O 3-δ (BCFZYA). The oxygen mobility, surface exchange kinetics, and bulk oxygen ion conductivity are all enhanced by 10%Al doping, as determined by EIS and performance tests. Moreover, Al doping led to the formation of the core-shell structure during the rearrangement of atoms. This results in an oxygen reduction reaction (ORR) of up to 0.157 cm2 at 520 oC on proton ion conducting electrolytes. As a result, BCFZYA appears to be a strong candidate for use in the cathode of advanced PCFCs (proton ceramic fuel cells). [Display omitted] • The BCFZYA cathode was prepared via the sol-gel method. • The BCFZYA has demonstrated higher fuel cell performance of 695 mW/cm2 at 520 oC. • The Al doping into BCFZY reveals better ORR activity of up to 0.157 cm2 at 520 oC on proton ion conducting electrolytes. • Core-shell structure and energy band alignment phenomena have been proposed. • The designed cathode has revealed a lower ASR value at 520 °C. [ABSTRACT FROM AUTHOR]