Zn–H+ Battery, Versatile Energy Conversion Equipment for Electricity Generation and H2 Production Simultaneously

Zn–H+ battery is a new energy conversion device, which can act as an electricity provider as well as an H2 generator. In general, the activity of the hydrogen evolution reaction (HER) electrocatalyst determines the performance of the Zn–H+ battery to a great extent. In our attempt, an inexpensive and effective HER electrocatalyst was synthesized successfully. In this electrocatalyst, the Cu based coordination complex loads onto filter paper derived three-dimensional mesoporous carbon paper homogeneously. Compared with traditional powder electrocatalysts, the bulky appearance of this electrocatalyst makes it possible that it can be employed as a binder-free electrode directly. In the acidic electrolyte, it exhibits perfect electrocatalytic activity. The η10 potential of this electrocatalyst is only 91 mV. This electrocatalyst also shows excellent durability after long time HER tests. With this electrocatalyst and Zn plate as cathode and anode, respectively, a Zn–H+ battery was assembled. The open circuit voltage of this battery is 1.18 V. Its peak power density arrives at 65.6 mW·cm–2. When discharged at 10 mA·cm–2, the voltage of this battery keeps stable for 10 h. In this process, the specific capacity and energy density of Zn–H+ battery are 768 mAh·g–1 and 875 Wh·kg–1, respectively. At this current density, its H2 production rate arrives at 578 μmol in 80 min, with a Faradaic efficiency 96.3%. This work opens a new research field for HER.