Institute for Frontier Materials, Deakin University, 221 Burwood Hwy, Burwood, Victoria, Australia.
Boron Molecular, 500 Princes Hwy, Noble Park, Victoria, Australia.
Chemphyschem. 2022 Jul 5;23(13):e202200115. doi: 10.1002/cphc.202200115. Epub 2022 May 17.
The implementation of next-generation batteries requires the development of safe, compatible electrolytes that are stable and do not cause safety problems. The difluoro(oxalato)borate ([DFOB] ) anion has been used as an electrolyte additive to aid with stability, but such an approach has most commonly been carried out using flammable solvent electrolytes. As an alternative approach, utilisation of the [DFOB] anion to make ionic liquids (ILs) or Organic Ionic Plastic Crystals (OIPCs) allows the advantageous properties of ILs or OIPCs, such as higher thermal stability and non-volatility, combined with the benefits of the [DFOB] anion. Here, we report the synthesis of new [DFOB] -based ILs paired with triethylmethylphosphonium [P ] , and diethylisobutylmethylphosphonium [P ] . We also report the first OIPCs containing the [DFOB] anion, formed by combination with the 1-ethyl-1-methylpyrrolidinium [C mpyr] cation, and the triethylmethylammonium [N ] cation. The traditional synthetic route using halide starting materials has been successfully replaced by a halide-free tosylate-based synthetic route that is advantageous for a purer, halide free product. The synthesised [DFOB] -based salts exhibit good thermal stability, while the ILs display relatively high ionic conductivity. Thus, the new [DFOB] -based electrolytes show promise for further investigation as battery electrolytes both in liquid and solid-state form.
下一代电池的实现需要开发安全、兼容的电解质，这些电解质应稳定且不会引发安全问题。双氟（草酸根）硼酸根 ([DFOB]) 阴离子已被用作电解质添加剂以提高稳定性，但此类方法通常是在使用易燃溶剂电解质的情况下进行的。作为一种替代方法，利用 [DFOB] 阴离子来制备离子液体 (ILs) 或有机离子塑料晶体 (OIPCs)，可以结合 ILs 或 OIPCs 的优势特性（如更高的热稳定性和非挥发性），同时结合 [DFOB] 阴离子的优势。在这里，我们报告了与三乙基甲基膦 [P ] 和二乙基异丁基甲基膦 [P ] 配对的新型 [DFOB] 基 ILs 的合成。我们还报告了首例含有 [DFOB] 阴离子的 OIPC，其由与 1-乙基-1-甲基吡咯烷鎓 [C mpyr] 阳离子和三乙基甲基铵 [N ] 阳离子结合形成。传统的使用卤化物起始原料的合成路线已成功被基于 tosylate 的无卤路线所取代，该路线有利于获得更纯净、无卤的产物。所合成的 [DFOB] 基盐表现出良好的热稳定性，而 ILs 则表现出较高的离子电导率。因此，新型 [DFOB] 基电解质有望进一步作为液体和固态电池电解质进行研究。
