Figure 5.

a) Open‐circuit voltage measurement, b) discharge curves, and c) polarization curve and power density plot of Zn–air batteries used DN‐UGNR and Pt/C electrodes. d) Discharge and charge cycling of rechargeable Zn–air batteries based on DN‐UGNR and the mixture of Pt/C+RuO₂ electrodes at the current density of 5 mA cm⁻². e) Rate capability behavior of Zn–air battery with DN‐UGNR electrode. Photograph of f) 22 parallel red and g–i) high‐voltage (orange, green, and blue, 3.0–3.2 V) LED lamp beads driven by two Zn–air batteries with the DN‐UGNR electrode connected in series.