Nitrogen Reduction Reaction at High Current-to-Ammonia Efficiency

Apart from its use in the fertiliser and chemical industries, ammonia is currently attracting our community as a potential carbon-neutral fuel and as an energy carrier for worldwide transportation of renewable sources. To achieve this goal, replacements of the conventional hydrocarbon deposit-based technology for NH3 production require to be a green but inexpensive and scale-flexible technology, namely the only genuine electrochemical lithium-mediated nitrogen reduction reaction (Li-NRR). Reported by many research groups around the world, the process had so far been hampered by poor yield rates and efficiencies. At Monash University, we introduced a compact ionic assembly arranged in the electrode-electrolyte interfacial region produced by a high-concentration imide-based lithium salt electrolyte to present a high-efficiency. This approach enables a stable electrode surface which electrolyte decomposition is suppressed, therefore closely approaching 100% current-to-ammonia efficiency whilst the ammonia yield rate can achieve as high as 8 kg day-1 m-2. However, the degradation of the electrolyte solution by unwanted processes on the anode is the biggest challenge, which urgently requires for the development of effective H2- or H2O-feed anodes. Our current findings and the future research achievements are believed to guide the development of a high-performance and sustainable ammonia electrosynthesis system.