上海交通大学魏光华团队报道了使用醚基电解质的锂介导氨的电合成。相关研究成果于2023年11月15日发表在《美国化学会杂志》。

氨在化肥生产和化学合成中具有重要意义。它还可能成为未来氢能经济的无碳能源载体。受全球降低碳排放努力的推动，通过锂介导的电化学氮还原（LiNR）合成氨被认为是Haber–Bosch工艺的一种有前途的替代方案。近年来，通过探索有利的锂盐和质子供体作为电解质配方，LiNR的性能得到了显著改善，但溶剂研究仍处于初级阶段。

该文中，研究人员对醚基溶剂在LiNR的应用进行了系统的研究。其导电性、寄生反应、产物分布和法拉第效率的基础上对候选溶剂进行了评估。值得注意的是，在所研究的系统中，二甲氧基乙烷的潜在损失最低，而四氢呋喃在环境压力下实现了58.5±6.1%的卓越法拉第效率。研究发现，溶剂分子通过决定导电离子的溶剂化构型，并诱导形成具有不同组成的固体电解质界面来影响上述特性。

该研究强调了溶剂在LiNR工艺中的重要性，并提出了电解质优化以获得更好的性能。

附：英文原文

Title: Lithium-Mediated Ammonia Electrosynthesis with Ether-Based Electrolytes

Author: Xiyang Cai, Xingdian Li, Jiabin You, Fan Yang, Zulipiya Shadike, Song Qin, Liuxuan Luo, Yangge Guo, Xiaohui Yan, Shuiyun Shen, Guanghua Wei, Zhichuan J. Xu, Junliang Zhang

Issue&Volume: November 15, 2023

Abstract: Ammonia is of great importance in fertilizer production and chemical synthesis. It can also potentially serve as a carbon-free energy carrier for a future hydrogen economy. Motivated by a worldwide effort to lower carbon emissions, ammonia synthesis by lithium-mediated electrochemical nitrogen reduction (LiNR) has been considered as a promising alternative to the Haber–Bosch process. A significant performance improvement in LiNR has been achieved in recent years by exploration of favorable lithium salt and proton donor for the electrolyte recipe, but the solvent study is still in its infancy. In this work, a systematic investigation on ether-based solvents toward LiNR is conducted. The assessments of solvent candidates are built on their conductivity, parasitic reactions, product distribution, and faradaic efficiency. Notably, dimethoxyethane gives the lowest potential loss among the investigated systems, while tetrahydrofuran achieves an outstanding faradaic efficiency of 58.5 ± 6.1% at an ambient pressure. We found that solvent molecules impact the above characteristics by dictating the solvation configurations of conductive ions and inducing the formation of solid electrolyte interphase with different compositions. This study highlights the importance of solvents in the LiNR process and advances the electrolyte optimization for better performance.

DOI: 10.1021/jacs.3c08965

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.3c08965