Among the many chemicals we use every day, ammonia is one of the worst for the atmosphere. The nitrogen-based chemical used in fertilizer, dyes, explosives and many other products ranks second only to cement in terms of carbon emissions, due to the high temperatures and energy needed to manufacture it. But by improving on a well-known electrochemical reaction and orchestrating a ‘symphony’ of lithium, nitrogen and hydrogen atoms, engineers have developed a new ammonia production process that meets several green targets.