Ammonia is a promising energy vector and can be used as a hydrogen storage medium. Electrocatalytic ammonia syntheses using renewable energy are attractive low-temperature options to the Haber-Bosch high-temperature process, which releases CO2 in the atmosphere and contributes to the greenhouse effect. High-entropy (HEA) alloys belong to a new class of materials that can provide single-phase stabilizations by mixing different species and are promising candidates to overcome scientific challenges posed by electrochemistry. Lithium-mediated ammonia synthesis is a way to get high-performance ammonia electrosynthesis from nitrogen at room temperature. In this work, we investigated lithium-mediated ammonia synthesis of a thin-film high-entropy catalyst of CoCrFeMnNi.