Unlocking Ambient Electrochemical Lithium–Mediated Nitrogen Reduction: Mechanisms, Classifications, Components and Perspectives

Comprehensive Summary Electrochemical lithium–mediated nitrogen reduction (LiNR) offers a sustainable alternative to the Haber‐Bosch process for ammonia synthesis but faces hurdles in reaction mechanisms and component optimization. This review critically analyzes recent advancements of LiNR, categorizing them into intermittent (ILiNR) and continuous (CLiNR) modes based on the operational strategies of proton sources. CLiNR is further classified by anode mechanisms: electrolyte oxidation, H 2 oxidation (HOR), and Li oxidation (LiOR). Integrating the lithium–nitrogen cell (Li–N 2 ) concept into LiNR highlights its distinct advantages, particularly in lithium sourcing, side reaction suppression, and lithium cycling. We comprehensively examine electrode materials, cell configurations, and electrolytes. The relationship between Li–N 2 and LiNR is analyzed. Divergences in cell design, operating voltage, cathode reaction mechanisms, and lithium cycling strategies are discussed to offer guidance for integrating Li–N 2 cells into LiNR. Future research should focus on elucidating the nitrogen fixation mechanism at low current densities, increasing current density to accelerate N 2 reaction rates, investigating the evolution of nitrogen‐fixing lithium‐containing interfaces, and introducing controlled trace proton sources to enhance interface permeability, in order to enable sustainable ammonia synthesis coupled with lithium cycling. Key Scientists Lithium‐mediated nitrogen reduction (LiNR) for ammonia synthesis has experienced remarkable development. The field witnessed its inception in 2017 with the pioneering report of the Li‐N 2 battery by Zhang et al. and intermittent ammonia synthesis (ILiNR) via a lithium‐cycling mechanism by Jens Nørskov and Ib Chorkendorff et al. In 2019, a protocol for continuous ammonia synthesis (CLiNR) was established and 15 N 2 isotope experiment confirmed its success. The development of kinetic models played a crucial role in this domain, contributions emerging in 2019, 2020, and 2022. The investigation of hydrogen oxidation (HOR) as the anode reaction garnered attention, due to its potential to mitigate electrolyte oxidation. Manthiram et al. were the first to incorporate the HOR in 2020, employing gas diffusion electrodes. In 2022, they explored the influence of proton sources on the reaction. MacFarlane et al. introduced the concept of the proton shuttle in 2021. In 2023, Fu et al. utilized a continuous flow reactor and D 2 isotope experiments to validate the source of protons. Zhang and Cai et al. explored the solvents and applied the membrane electrode. In 2024, Li et al. achieved long‐term continuous ammonia synthesis. Since 2022, Sun and Ma et al. focused on integrating Li‐N 2 and LiNR methodologies. In 2024, they highlighted the advantages of lithium anode and proposed that both lithium oxidation reduction (LiOR) and HOR could suppress electrolyte oxidation, potentially enabling continuous lithium‐cycling‐based ammonia synthesis. This review synthesizes the mechanistic insights at both the cathode and anode. It also focuses on common themes related to electrodes, cells, and electrolytes. Finally, the manuscript offers a perspective on the future research directions for Li‐N 2 cell and LiNR.