Cheaper Electrolyte for Aluminium-Ion Batteries

Aluminium-ion batteries (AIBs) use earth-abundant materials, have a high performance, and are generally safer than lithium-ion batteries. These properties could make them suitable for large-scale energy storage. However, currently available AIBs use the expensive ionic liquid 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl), mixed with aluminium chloride, as an electrolyte.

Thomas Nann, Victoria University of Wellington, New Zealand, and colleagues have developed a low-cost alternative electrolyte for AlBs. The team added AlCl₃ to anhydrous acetamide under a nitrogen atmosphere to form an eutectic mixture. The resulting pale yellow ionic liquid contains species such as [H₃CCONH₂–AlCl₂]⁺ and [AlCl₄]^–.

The prepared ionic liquids were tested as an electrolyte in an electrochemical cell simulating an AlB. The team found charge/discharge profiles which were very similar to those of traditional [EMIm]Cl-based electrolytes. The performance of the acetamide-based electrolyte could be further improved by diluting it with dichloromethane to reduce its viscosity. Acetamide is significantly cheaper than [EMIm]Cl and, thus, this development could reduce the production costs of AIBs significantly.

• Acetamide: a low-cost alternative to alkyl imidazolium chlorides for aluminium-ion batteries,
  Nicolo Canever, Nicolas Bertrand, Thomas Nann,
  Chem. Commun. 2018.
  https://doi.org/10.1039/c8cc04468f

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