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10000‐Fold Enhancement in Proton Conduction by Doping of Cesium Ions in a Proton‐Conducting Zwitterionic Metal–Organic Framework
Author(s) -
Shalini Sorout,
Aggarwal Shubhangi,
Singh Santosh K.,
Dutt Malvika,
Ajithkumar Thallaseril G.,
Vaidhyanathan Ramanathan
Publication year - 2016
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201600364
Subject(s) - chemistry , ion , proton , caesium , conductivity , metal ions in aqueous solution , electrolyte , doping , amorphous solid , metal , metal organic framework , ionic bonding , ionic radius , thermal conduction , chemical physics , inorganic chemistry , chemical engineering , crystallography , organic chemistry , electrode , optoelectronics , materials science , composite material , adsorption , physics , quantum mechanics , engineering
Developing metal–organic framework (MOF)‐based proton‐conducting electrolytes for fuel‐cell applications is an important target that has drawn a lot of attention. A key approach involves the selective replacement of the guest species within the pores to enhance performance. The modular and crystalline nature of the MOF permits controlled introduction of such species and characterization of their compositions with high precision, a task which is very difficult to achieve in amorphous polymers. Herein, we partially replaced the protons of a zwitterionic pyridinol in Mg(terephthalate)(pyridinol) MOF 1 with Cs + ions, which brought about a 10000‐fold increase in the proton conductivity (10 –6 to 10 –2 S cm –1 ). Interestingly, Li + ions could not be loaded, whereas Cs + ions with smaller hydrated ionic radii could be loaded, and the loading was controlled as a function of time. The Cs + loading nearly halved the activation energy (from 0.35 for 1 to 0.19 eV for 1 _Cs). The highest conductivities were realized for an optimal loading of Cs + ions, which was found to be about 10 % in this case.