960化工网
Towards understanding of electrolyte degradation in lithium-mediated non-aqueous electrochemical ammonia synthesis with gas chromatography-mass spectrometry†
Rokas Sažinas,Suzanne Zamany Andersen,Katja Li,Mattia Saccoccio,Kevin Krempl,Jakob Bruun Pedersen,Jakob Kibsgaard,Peter Christian Kjærgaard Vesborg,Debasish Chakraborty,Ib Chorkendorff
RSC Advances Pub Date : 09/23/2021 00:00:00 , DOI:10.1039/D1RA05963G
Abstract

Lithium-mediated electrochemical ammonia synthesis (LiMEAS) in non-aqueous media is a promising technique for efficient and green ammonia synthesis. Compared to the widely used Haber–Bosch process, the method reduces CO2 emissions to zero due to the application of green hydrogen. However, the non-aqueous medium encounters the alkali metal lithium and organic components at high negative potentials of electrolysis, which leads to formation of byproducts. To assess the environmental risk of this synthesis method, standardized analytical methods towards understanding of the degradation level and consequences are needed. Here we report on the implementation of an approach to analyze the liquid electrolytes after electrochemical ammonia synthesis via high-resolution gas chromatography-mass spectrometry (GCMS). To characterize the molecular species formed after electrolysis, electron ionization high-resolution mass spectrometry (EI-MS) was applied. The fragmentation patterns enabled the elucidation of the mechanisms of byproduct formation. Several organic electrolytes were analyzed and compared both qualitatively and quantitatively to ascertain molecular composition and degradation products. It was found that the organic solvent in contact with metallic electrodeposited lithium induces solvent degradation, and the extent of this decomposition to different organic molecules depends on the organic solvent used. Our results show GCMS as a suitable technique for monitoring non-aqueous electrochemical ammonia synthesis in different organic electrolytes.

Graphical abstract: Towards understanding of electrolyte degradation in lithium-mediated non-aqueous electrochemical ammonia synthesis with gas chromatography-mass spectrometry
平台客服
平台客服
平台在线客服