Li Shaofeng, Zhou Yuanyuan, Li Katja, Saccoccio Mattia, Sažinas Rokas, Andersen Suzanne Z, Pedersen Jakob B, Fu Xianbiao, Shadravan Vahid, Chakraborty Debasish, Kibsgaard Jakob, Vesborg Peter C K, Nørskov Jens K, Chorkendorff Ib
Department of Physics, Technical University of Denmark, Kongens Lyngby, Denmark.
Joule. 2022 Sep 21;6(9):2083-2101. doi: 10.1016/j.joule.2022.07.009.
Ammonia is a large-scale commodity essential to fertilizer production, but the Haber-Bosch process leads to massive emissions of carbon dioxide. Electrochemical ammonia synthesis is an attractive alternative pathway, but the process is still limited by low ammonia production rate and faradaic efficiency. Herein, guided by our theoretical model, we present a highly efficient lithium-mediated process enabled by using different lithium salts, leading to the formation of a uniform solid-electrolyte interphase (SEI) layer on a porous copper electrode. The uniform lithium-fluoride-enriched SEI layer provides an ammonia production rate of 2.5 ± 0.1 μmol s cm at a current density of -1 A cm with 71% ± 3% faradaic efficiency under 20 bar nitrogen. Experimental X-ray analysis reveals that the lithium tetrafluoroborate electrolyte induces the formation of a compact and uniform SEI layer, which facilitates homogeneous lithium plating, suppresses the undesired hydrogen evolution as well as electrolyte decomposition, and enhances the nitrogen reduction.
氨是化肥生产必不可少的大规模商品，但哈伯-博施法会导致大量二氧化碳排放。电化学合成氨是一种有吸引力的替代途径，但该过程仍受氨生产率低和法拉第效率的限制。在此，在我们的理论模型指导下，我们提出了一种高效的锂介导过程，通过使用不同的锂盐实现，从而在多孔铜电极上形成均匀的固体电解质界面（SEI）层。均匀的富含氟化锂的SEI层在20巴氮气下，在-1 A cm²的电流密度下提供2.5±0.1 μmol s⁻¹ cm⁻²的氨生产率，法拉第效率为71%±3%。实验X射线分析表明，四氟硼酸锂电解质诱导形成致密且均匀的SEI层，这有利于均匀的锂镀层，抑制不希望的析氢以及电解质分解，并增强氮还原。
