Temporally Decoupled Ammonia Splitting by a Zn-NH Battery with an Ammonia Oxidation/Hydrogen Evolution Bifunctional Electrocatalyst as a Cathode.

Ammonia splitting to hydrogen is a decisive route for hydrogen economy but is seriously limited by the complex device and low efficiency. Here, we design and propose a new rechargeable Zn-NH battery based on temporally decoupled ammonia splitting to achieve efficient NH-to-H conversion. In this system, ammonia is oxidized into nitrogen during cathodic charging (2NH + 6OH → N + 6HO + 6e) with external electrical energy conversion and storage, while during cathodic discharging, water is reduced to hydrogen (2HO + 2e → H + 2OH) with electrical energy generation. In this loop, continuous and efficient H production without separation and purification is achieved. With the help of the ammonia oxidation reaction (AOR) and hydrogen evolution reaction (HER) bifunctional catalyst of MoC/NiCu@C, a rechargeable Zn-NH battery is realized that exhibits a high NH-to-H FE of 91.6% with outstanding durability for 900 cycles (300 h) at 20 mA/cm, enabling efficient and continuous NH-to-H conversion.