Hydrogen generation via electrochemical splitting plays an important role to achieve hydrogen economy. However, the large-scale application is highly limited by high cost and low efficiency. Herein, a new type of rechargeable Zn-hydrazine (Zn-Hz) battery is proposed and realized by a bifunctional electrocatalyst based on two separate cathodic reactions of hydrogen evolution (discharge: 2H2 O + 2e- → H2 + 2OH- ) and hydrazine oxidation (charge: ). This Zn-Hz battery, driven by temporally decoupled electrochemical hydrazine splitting on the cathode during discharge and charge processes, can generate separated hydrogen without purification. When the highly active bifunctional cathode of 3D Mo2 C/Ni@C/CS is paired with Zn foil, the Zn-Hz battery can achieve efficient hydrogen generation with a low energy input of less than 0.4 V (77.2 kJ mol-1 ) and high energy efficiency of 96%. Remarkably, this battery exhibits outstanding long-term stability for 600 cycles (200 h), achieving continuous hydrogen production on demand, which presents great potential for practical application.
Keywords: Zn-hydrazine batteries; bifunctional electrocatalysts; decoupled electrochemical hydrazine splitting; separate hydrogen generation.
© 2022 Wiley-VCH GmbH.