Surface‐Engineered Homostructure for Enhancing Proton Transport

Abstract

Ultra‐wide bandgap semiconductor samarium oxide attracts great interest because of its high stability and electronic properties. However, the ionic transport properties of Sm2O3 have rarely been studied. In this work, Ni doping is proposed to be used for electronic structure engineering of Sm2O3. The formation of Ni‐doping defects lowers the Fermi level to induce a local electric field, which greatly enhances the proton transport at the surface. Furthermore, ascribed to surface modification, the high concentration of vacancies and lattice disorder on the surface layer promote proton transport. A high‐performance of 1438 mW cm–2 and ionic conductivity of 0.34 S cm–1 at 550 °C have been achieved using 3% mol Ni doped Sm2O3 as electrolyte for fuel cells. The well‐dispersed Ni doped surface in Sm2O3 builds up continuous surfaces as proton channels for high‐speed transport. In this work, a new methodology is presented to develop high‐performance, low‐temperature ceramic fuel cells.

NASICON-Type Lithium-Ion Conductor Materials with High Proton Conductivity Enabled by Lithium Vacancies

“…And the O 1s XPS spectra in Li 2.5 Sr 0.75 Zr 1.25 (PO 4 ) 3 could be fitted into three peaks at 532.94, 531.61, and 530.82 eV, which are assigned to the lattice oxygen atoms, oxygen atoms neighboring defects and oxygen atoms of the surface. 35,41,42 The ratio O v /O L for Li 2.5 Sr 0.75 Zr 1.25 (PO 4 ) 3 was significantly higher than SrZr 4 (PO 4 ) 6 , indicating that there are more oxygen vacancies. The increased amount of deficient oxygen species is ascribed to the doping of Sr 2+ in the sites of Zr 4+ .…”

Built-in Electric Field for Efficient Charge Separation and Ionic Transport in LiCoO2/SnO2 Semiconductor Junction Fuel Cells

“…However, the conventional yttrium-stabilized zirconia (YSZ) electrolyte cannot achieve sufficient ionic conductivity of 0.1 S cm –1 until ∼1000 °C, so the SOFC must be operated at high temperatures to achieve the desired performance, leading to several chemical-thermo-mechanical limitations that delay commercialization. − The single-layer (component) fuel cell (SLFC) or the electrolyte layer free fuel cell is gaining attention in recent research developments because it removes the limitations imposed by the electrolyte, resulting in far fewer material selection constraints than conventional three-layer anode/electrolyte/cathode fuel cells. It is also reported that the p–n heterojunctions or Schottky junctions play an extremely important role in overcoming the short circuit problem and improving power output. − …”

Sodium-Doped Samarium Oxide Electrolytes for Avoiding the Lithiation-Induced Interface Degradation of Ni0.8Co0.15Al0.05LiO2 Electrode-Based Ceramic Fuel Cells

“…In recent years, novel symmetrical CFCs using lithium compounds, that is, Ni 0.8 Co 0.15 Al 0.05 LiO 2 (NCAL) as electrodes with a cell configuration of NCAL/electrolyte/NCAL were reported for low temperatures. − These fuel cells have intriguing potential toward commercialization because of good performance and high ionic conductivity below 600 °C. − Some researchers reported that the high ionic conductivity is attributed to the surface/interface ionic transportation. − For example, Xing et al reported that high concentrations of oxygen vacancies in the CeO 2 surface layer promote the proton transportation . Super proton conductivity of 0.16 S cm –1 was achieved in the as-prepared CeO 2 electrolyte at 520 °C, which is much higher than the bulk oxygen ionic conductivity in doped cerium oxide. , However, the electrolyte is porous in these cells because they are fabricated with the dry press method and have not been sintered at high temperatures.…”