Garcia-Quintana Laura, Ortiz-Vitoriano Nagore, Zhu Haijin, Nolis Gene M, Herrero-Martín Javier, Echeverría María, López Del Amo Juan Miguel, Forsyth Maria, Bond Alan M, Howlett Patrick C, Pozo-Gonzalo Cristina
ARC Centre of Excellence for Electromaterials Science, Institute for Frontier Materials, Deakin University, Geelong, Victoria 3200, Australia.
Centre for Cooperative Research on Alternative Energies (CIC energiGUNE), Basque Research and Technology Alliance (BRTA), Parque Tecnológico de Alava, Albert Einstein 48, Vitoria-Gasteiz 01510, Spain.
ACS Appl Mater Interfaces. 2022 Jan 26;14(3):4022-4034. doi: 10.1021/acsami.1c20257. Epub 2022 Jan 12.
A series of hybrid electrolytes composed of diglyme and ionic liquids (ILs) have been investigated for Na-O batteries, as a strategy to control the growth and purity of the discharge products during battery operation. The dependence of chemical composition of the ILs on the size, purity, and distribution of the discharge products has been evaluated using a wide range of experimental and spectroscopic techniques. The morphology and composition of the discharge products found in the Na-O cells have a complex dependence on the physicochemical properties of the electrolyte as well as the speciation of the Na and superoxide radical anion. All of these factors control the nucleation and growth phenomena as well as electrolyte stability. Smaller discharge particle sizes and largely homogeneous (2.7 ± 0.5 μm) sodium superoxide (NaO) crystals with only 9% of side products were found in the hybrid electrolyte containing the pyrrolidinium IL with a linear alkyl chain. The long-term cyclability of Na-O batteries with high Coulombic efficiency (>90%) was obtained for this electrolyte with fewer side products (20 cycles at 0.5 mA h cm). In contrast, rapid failure was observed with the use of the phosphonium-based electrolyte, which strongly stabilizes the superoxide anion. A high discharge capacity (4.46 mA h cm) was obtained for the hybrid electrolyte containing the pyrrolidinium-based IL bearing a linear alkyl chain with a slightly lower value (3.11 mA h cm) being obtained when the hybrid electrolyte contained similar pyrrolidinium-based IL bearing an alkoxy chain.
一系列由二甘醇二甲醚和离子液体（ILs）组成的混合电解质已被用于钠氧电池的研究，作为一种在电池运行过程中控制放电产物生长和纯度的策略。使用了广泛的实验和光谱技术来评估离子液体的化学成分对放电产物的尺寸、纯度和分布的依赖性。在钠氧电池中发现的放电产物的形态和组成对电解质的物理化学性质以及钠和超氧自由基阴离子的形态有着复杂的依赖性。所有这些因素都控制着成核和生长现象以及电解质的稳定性。在含有具有线性烷基链的吡咯烷鎓离子液体的混合电解质中，发现了较小的放电颗粒尺寸和基本上均匀（2.7±0.5μm）的超氧化钠（NaO）晶体，副产物仅占9%。对于这种副产物较少的电解质，钠氧电池在高库仑效率（>90%）下具有长期循环稳定性（在0.5 mA h cm下循环20次）。相比之下，使用能强烈稳定超氧阴离子的鏻基电解质时，观察到电池迅速失效。对于含有具有线性烷基链的吡咯烷鎓基离子液体的混合电解质，获得了较高的放电容量（4.46 mA h cm）；当混合电解质含有类似的带有烷氧基链的吡咯烷鎓基离子液体时，放电容量略低（3.11 mA h cm）。
