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J Am Chem Soc. 2013 Feb 13;135(6):2076-9. doi: 10.1021/ja311518s. Epub 2013 Feb 1.
A major challenge in the development of rechargeable Li-O(2) batteries is the identification of electrolyte materials that are stable in the operating environment of the O(2) electrode. Straight-chain alkyl amides are one of the few classes of polar, aprotic solvents that resist chemical degradation in the O(2) electrode, but these solvents do not form a stable solid-electrolyte interphase (SEI) on the Li anode. The lack of a persistent SEI leads to rapid and sustained solvent decomposition in the presence of Li metal. In this work, we demonstrate for the first time successful cycling of a Li anode in the presence of the solvent, N,N-dimethylacetamide (DMA), by employing a salt, lithium nitrate (LiNO(3)), that stabilizes the SEI. A Li-O(2) cell containing this electrolyte composition is shown to cycle for more than 2000 h (>80 cycles) at a current density of 0.1 mA/cm(2) with a consistent charging profile, good capacity retention, and O(2) detected as the primary gaseous product formed during charging. The discovery of an electrolyte system that is compatible with both electrodes in a Li-O(2) cell may eliminate the need for protecting the anode with a ceramic membrane.
在可充电 Li-O(2) 电池的发展中,面临的一个主要挑战是确定在 O(2)电极的工作环境中稳定的电解质材料。直链烷基酰胺是少数几类在 O(2)电极中化学稳定性良好的极性、非质子溶剂之一,但这些溶剂在 Li 阳极上不能形成稳定的固体电解质界面 (SEI)。缺乏持久的 SEI 会导致在 Li 金属存在下溶剂迅速且持续分解。在这项工作中,我们首次通过使用一种盐,硝酸锂 (LiNO(3)),成功地在溶剂 N,N-二甲基乙酰胺 (DMA) 存在下循环 Li 阳极,该盐稳定了 SEI。结果表明,含有这种电解质组成的 Li-O(2) 电池在 0.1 mA/cm(2) 的电流密度下循环 2000 小时以上 (>80 次循环),充电曲线一致,容量保持良好,并且在充电过程中检测到 O(2) 是主要形成的气态产物。发现一种与 Li-O(2) 电池的两个电极都兼容的电解质体系,可能无需使用陶瓷膜来保护阳极。