1H-NMR measurements of proton mobility in nano-crystalline YSZ

Abstract

We report nuclear magnetic resonance (NMR) results on water saturated, dense, nano-crystalline YSZ samples (9.5 mol% yttria doped zirconia) which exhibit proton conductivity at temperatures as low as room temperature. originating from protons in the sample interior. For these protons, the analysis of temperature and field dependent spin-lattice relaxation time T 1 points towards diffusion in a confined two-dimensional geometry. We attribute this quasi two-dimensional motion to protons that are mobile along internal interfaces or nanopores of nano-crystalline YSZ.

Review: recent progress in low-temperature proton-conducting ceramics

“…Although samples prepared at relatively low pressures require high sintering temperature (800-1000°C), SPS has been a proven method to successfully fabricate samples with nanoscale grain features. Hinterberg et al [133] reported a spark- Figure 10 Schematic of the protonic species on nano grain surface (upper) and ultra-high-pressure compaction of nano grain (lower). Reprinted with permission from Miyoshi et al [24].…”

Spatial confinement – rapid 2D F−diffusion in micro- and nanocrystalline RbSn2F5

“…Such a value is relatively high but in agreement with similar observations for surface diffusion. 83 Obviously, F diffusion along the buried or inner planes 84 of RbSn 2 F 5 resembles ion dynamics on surfaces.…”

Mechanisms of Protonic Surface Transport in Porous Oxides: Example of YSZ

“…3 Ceramic Y-stabilized ZrO 2 (YSZ), known as a pure oxide ion conductor under a broad range of conditions, remarkably has shown protonic conduction at low temperatures. [1][2][4][5][6][7][8] Other ceramic oxides such as CeO 2 9-13 and TiO 2 , 3, 14-15 SiO 2 gels and glasses, [16][17][18][19][20] and functionalized porous SiO 2 21-24 also show similar behaviour. Moreover, particle hydrates, investigated in the early 1990's [25][26][27] , and humidity sensors based on the conductivity of porous oxides [28][29] are other examples of protonic conduction in porous oxides known under other names.…”

“…Proton conduction in adsorbed water in porous nanocrystalline oxides is attracting attention for use in various electrochemical devices at near-ambient temperatures. , As an example, the conductivity of a porous thin film of anatase is reported to be as high as 3.8 × 10 –2 S cm –1 at 80 °C and 81% relative humidity (RH) . Ceramic Y-stabilized ZrO 2 (YSZ), known as a pure oxide ion conductor under a broad range of conditions, remarkably has shown protonic conduction at low temperatures. ,,− Other ceramic oxides such as CeO 2 − and TiO 2 , ,, SiO 2 gels and glasses, − and functionalized porous SiO 2 − also show similar behavior. Moreover, particle hydrates, investigated in the early 1990s, − and humidity sensors based on the conductivity of porous oxides , are other examples of protonic conduction in porous oxides known under other names.…”