Reversibly Electrochemical Ethylamine/Acetonitrile Redox for Hydrogen Storage

ABSTRACT Hydrogen (H ₂ ) storage/release technology is a core aspect of achieving large‐scale application of hydrogen energy. Liquid organic hydrogen carrier (LOHC) is a promising H ₂ storage method owing to their high hydrogen storage capacity, safety, and transportation convenience, while suffers from the high temperature and pressures conditions during H ₂ storage and release. Herein, we report a water‐mediated electrochemical ethylamine (EA)/acetonitrile (AN) redox system with a high theoretical H ₂ storage capacity (8.9 wt.%). Specifically, the storage and release systems comprise the hydrogenation of AN to EA with a selectivity of > 92% and the electrooxidation of EA back to AN with a selectivity of > 99%, respectively. Mechanism measurements indicate that H ₂ storage and release utilize water as the hydrogen source, demonstrating this strategy is green and safe in nature, along with its ease of operation. As a proof of concept, we employed a two‐electrode flow electrolyzer for H ₂ storage and release, attaining 5 mmol cm ⁻² h ⁻¹ of H ₂ storage rate and 7 mmol cm ⁻² h ⁻¹ of H ₂ production rate at 1.5 A. Furthermore, we used the integration of the electrochemical conversion system with a distillation unit achieved a H ₂ storage density of 8.9 wt.%, providing a viable route for hydrogen storage and release.