Insights from impedance spectroscopy into the mechanism of thermal decomposition of M(NH2BH3), M = H, Li, Na, Li0.5Na0.5, hydrogen stores
Insights from impedance spectroscopy into the mechanism of thermal decomposition of M(NH2BH3), M = H, Li, Na, Li0.5Na0.5, hydrogen stores
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DOI：
10.1039/c2cp23344d
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发表时间：
2012-01-01
影响因子：
3.3
通讯作者：
Grochala, Wojciech
中科院分区：
文献类型：
--
作者：
Fijalkowski, Karol J.;Jurczakowski, Rafa;Grochala, Wojciech
We report the first solid-state impedance study of hydrogen-rich ammonia borane, AB, and its three alkali metal amidoborane derivatives. Temperature-dependent impedance spectra of solid M(NH2BH3) salts are predominated by ionic conductivity, which at room temperature ranges from 5.5 mu S cm(-1) (M = Li) to 2.2-3.0 mS cm(-1) (Na, Na0.5Li0.5), while the activation energy for conductivity is rather high (140-158 kJ mol(-1)). Variation of conductivity with time can be used to extract information about the evolution of the system during thermal decomposition. By using a combination of impedance spectroscopy, thermogravimetric analysis, scanning calorimetry, evolved gas analysis, infrared absorption spectroscopy as well as B-11 and H-1 MAS NMR, we were able to reconfirm the complex pathway of thermal decomposition of amidoboranes postulated by two of us earlier (J. Mater. Chem. 2009, 19, 2043).
