The conversion of atmospheric nitrogen (N 2 ) into valuable substances such as fine chemicals and fertilizers is critical to industry, agriculture, and many other processes that sustain human life. However, because the N≡N bond in N 2 is one of the strongest available, N 2 fixation is a kinetically complex and energetically challenging reaction. Up until now, it has heavily relied on the energy- and capital-intensive Haber-Bosch process, wherein the input of H 2 and energy is largely derived from fossil fuels, thus resulting in large amounts of CO 2 emission. Electrocatalytic N 2 fixation represents an attractive prospect. Unfortunately, given the lack of an efficient process, the production yields and faradic efficiency are still rather poor. In this work, we propose and demonstrate a rechargeable Li-N 2 battery with the reversible reaction of 6Li + N 2 ⇋ 2Li 3 N. The battery shows a promising electrochemical faradic efficiency (59%) and good cycle performance.