TY - JOUR
T1 - Enhancing Solid-State Conductivity through Acid or Base Doping of Protic Imidazolium and Imidazolinium Triflate Salts
AU - Chong, Alison L.
AU - Zhu, Haijin
AU - Nairn, Kate M.
AU - Forsyth, Maria
AU - Macfarlane, Douglas R.
N1 - Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/12/21
Y1 - 2017/12/21
N2 - Protic salts, including those showing plastic crystal behavior, are an interesting family of materials being rediscovered for use as solid conducting materials. This work compares two such compounds, 2-methylimidazolium triflate, [2-MeHIm][TfO], and 2-methylimidazolinium triflate, [2-MeHImn][TfO]. This subtle change in structure resulted in substantial differences in thermal behavior; [2-MeHIm][TfO] shows two solid-solid phase transitions while none were observed for [2-MeHImn][TfO]. However, both compounds are in a disordered solid state (ΔSf < 40 JK-1 mol-1) resulting in relatively high room temperature conductivities. Neat [2-MeHImn][TfO] had a conductivity above 10-5 S cm-1, but the addition of either the component acid or base as dopants resulted in a substantial increase in conductivity, to over 10-4 S cm-1 at 30 °C. Solid-state 1H and 19F NMR studies suggest that the dopants enhance the conduction primarily by increasing the proportion of mobile ions in the solid matrix. However, [2-MeHIm][TfO] also displays evidence of proton hopping via the cation.
AB - Protic salts, including those showing plastic crystal behavior, are an interesting family of materials being rediscovered for use as solid conducting materials. This work compares two such compounds, 2-methylimidazolium triflate, [2-MeHIm][TfO], and 2-methylimidazolinium triflate, [2-MeHImn][TfO]. This subtle change in structure resulted in substantial differences in thermal behavior; [2-MeHIm][TfO] shows two solid-solid phase transitions while none were observed for [2-MeHImn][TfO]. However, both compounds are in a disordered solid state (ΔSf < 40 JK-1 mol-1) resulting in relatively high room temperature conductivities. Neat [2-MeHImn][TfO] had a conductivity above 10-5 S cm-1, but the addition of either the component acid or base as dopants resulted in a substantial increase in conductivity, to over 10-4 S cm-1 at 30 °C. Solid-state 1H and 19F NMR studies suggest that the dopants enhance the conduction primarily by increasing the proportion of mobile ions in the solid matrix. However, [2-MeHIm][TfO] also displays evidence of proton hopping via the cation.
UR - http://www.scopus.com/inward/record.url?scp=85038613564&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.7b10275
DO - 10.1021/acs.jpcc.7b10275
M3 - 文章
AN - SCOPUS:85038613564
SN - 1932-7447
VL - 121
SP - 27849
EP - 27859
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 50
ER -