Lithium-mediated nitrogen reduction to ammonia via the catalytic solid–electrolyte interphase

Abstract

The lithium-mediated nitrogen reduction reaction (LiNRR) produces ammonia in ambient conditions. This electrochemical pathway is dependent on a catalytic solid–electrolyte interphase—a nanoscale passivation layer formed from reductive electrolyte decomposition on the surface of lithium metal. The catalytic solid–electrolyte interphase is a unique nanostructured environment that exists on reactive metal surfaces and intimately influences product selectivity. Here we explore recent progress made in the field of lithium-mediated nitrogen reduction to ammonia, especially in light of growing knowledge about the nature of the catalytic solid–electrolyte interphase. We systematically analyse the observed chemical species and reactions that occur within the solid–electrolyte interphase. We also summarize key developments in kinetic and transport models, as well as highlight the cathodic and complementary anodic reactions. Trends in ammonia selectivities and rates with varying electrolyte compositions, cell designs and operating conditions are extracted and used to articulate a path forward for continued development of lithium-mediated nitrogen reduction to ammonia. The electrochemical synthesis of ammonia via the lithium-mediated reduction of N2 holds great promise to replace the carbon- and energy-intensive Haber–Bosch process. This Review discusses this approach and examines the critical role of the catalytic solid–electrolyte interphase formed on the electrode.