Ammonia is crucial in fertilizer and chemical industries and is seen as a carbon-free fuel¹. The ammonia electrosynthesis from nitrogen at ambient conditions offers an attractive alternative to the Haber-Bosch process^2,3. The lithium-mediated nitrogen reduction (Li-NRR) represents a promising approach for continuous-flow ammonia electrosynthesis, coupling nitrogen reduction with hydrogen oxidation⁴. However, tetrahydrofuran (THF), commonly used as a solvent, impedes long-term ammonia production due to polymerization and volatility issues. Here we show that a chain ether-based electrolyte enables long-term continuous ammonia synthesis. We find that a chain ether-based solvent exhibits non-polymerization properties, a high boiling point (162 °C), and forms a compact solid-electrolyte interphase (SEI) layer on the gas diffusion electrode (GDE), facilitating ammonia release in the gas phase and ensuring electrolyte stability. We demonstrate 300 h continuous operation in a flow electrolyzer with 25 cm² electrode at 1 bar and room temperature, and achieve a current-to-ammonia efficiency of 64 ± 1% with unprecedented gas phase ammonia content of ~ 98%. Our work highlights the crucial role of the solvent in long-term continuous ammonia synthesis.

氨在化肥和化学工业中至关重要，被视为一种无碳燃料¹。在环境条件下用氮气电合成氨为哈伯-博世工艺提供了一种有吸引力的替代方案^2,3。锂介导的氮还原（Li-NRR）代表了一种有前途的连续流氨电合成方法，将氮还原与氢氧化结合起来⁴。然而，常用作溶剂的四氢呋喃 (THF) 由于聚合和挥发性问题而阻碍了氨的长期生产。在这里，我们展示了基于链醚的电解质能够实现长期连续的氨合成。我们发现链醚基溶剂表现出非聚合特性、高沸点（162℃），并在气体扩散电极（GDE）上形成致密的固体电解质界面（SEI）层，促进氨在气体扩散电极（GDE）上的释放。气相并确保电解质稳定性。^{我们在具有 25 cm 2}电极的流动电解槽中在 1 bar 和室温下演示了 300 小时的连续运行，并实现了 64 ± 1% 的电流氨效率，气相氨含量达到前所未有的 ~ 98%。我们的工作强调了溶剂在长期连续氨合成中的关键作用。