Conductivity of the Chloroaluminate Melt Based on Triethylamine Hydrochloride

A high cost of organic components of electrolytes is one of the main problems retarding the large-scale production of aluminum-ion batteries (AIBs). A chloroaluminate melt, or ionic liquid (IL) based on triethylamine hydrochloride (Et3NHCl), can be considered as a cheaper analogue. The AlCl3–Et3NHCl IL has a relatively high conductivity and crystallization temperature lower than room temperature at certain ratios of aluminum chloride to the organic salt. The single studies of the model of AIBs with the AlCl3–Et3NHCl IL show that the use of the electrolyte considered is promising. However, detailed studies devoted to the conductivity at different AlCl3 contents are lacking from periodicals, while they are necessary for establishing optimum electrolyte compositions. The conductivity of the IL is shown to increase sharply from 23.35 to 60.67 mS cm–1 with an increase in the aluminum chloride concentration in basic (according to Lewis) ILs and decreases from 60.67 to 37.31 mS cm–1 with an increase in the aluminum chloride content in acidic ILs at 100°C. The sharp change in the conductivity on the temperature dependences is due to the melting/crystallization of the IL, which is consistent with the published thermal analysis results. The activation energy of conductivity remains unchanged in the acidic AlCl3–Et3NHCl ILs within the calculation inaccuracy and is equal to 16.7 ± 0.3 kJ mol–1.