Dielectric Properties of 1-ethyl-3-methyl-imidazolium Tetrafluoroborate (EMIM-BF4) Using Cole-Cole Relaxation Model

The Cole-Cole relaxation equations were derived from the Debye equation. The dielectric constant E’ and loss factor E” of EMIM-BF4 were fitted using the derived equations at temperature range of 5°C to 65°C and frequency range of 0.1GHz to 10GHz. The result obtained shows that the dielectric constant and loss factor of EMIM-BF4 were higher at low frequency (i.e. f =0.1GHZ and decrease as the frequency increases. The dielectric constant also increases with increase in the temperature except at 0.1GHz. At 15°C there was a sudden increase in the dielectric constant especially as the frequency increases beyond 5GHz. This sudden increase in the dielectric constant of EMIM-BF4 may be due to the phase change of EMIM-BF4. The loss factor of EMIM-BF4 was generally small for all frequencies and temperatures. This may be due to the fact that EMIM-BF4 consumed less energy when subjected to an applied field.