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Lookup NU author(s): Professor Ulrich Stimming
This is the authors' accepted manuscript of an article that has been published in its final definitive form by American Chemical Society , 2018.
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We demonstrate that (NH4)2Si0.5Ti0.5P4O13 is an excellent proton conductor. The crystallographic information concerning the hydrogen positions is for the first time unraveled from neutron powder diffraction (NPD) data. This study shows that all the hydrogen atoms are connected though H-bonds, establishing a two-dimensional path between [(Si0.5Ti0.5)P4O132-]n layers for the proton diffusion across the crystal structure, by breaking and reconstructing intermediate H–O=P bonds. This transient species probably reduces the potential energy of the H jump from an ammonium unit to the next neighboring NH4+ unit. Both theoretical and experimental results support an interstitial proton conduction mechanism. The proton conductivities of (NH4)2Si0.5Ti0.5P4O13 reach 0.0061 and 0.024 S cm-1 in humid air at 125 oC and 250 oC, respectively. This finding demonstrates that (NH4)2Si0.5Ti0.5P4O13 is a promising electrolyte material operating at 150-250oC. This work opens up a new avenue for designing and fabricating high-performance inorganic electrolytes.
Author(s): Sun C, Chen L, Shi S, Reeb B, Lopez CA, Alonso JA, Stimming U
Publication type: Article
Publication status: Published
Journal: Inorganic Chemistry
Print publication date: 16/01/2018
Online publication date: 02/01/2018
Acceptance date: 20/12/2017
Date deposited: 21/12/2017
ISSN (print): 0020-1669
ISSN (electronic): 1520-510X
Publisher: American Chemical Society
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