An Aqueous Hybrid Zinc-Bromine Battery with High Voltage and Energy Density

The zinc-bromine redox flow battery (ZBB) is an ideal device of energy storage systems. Nevertheless, its energy density is relatively low compared to those of Li-ion batteries, due to its low output voltage. Herein, a high-voltage aqueous hybrid zinc-bromine battery system (AHZBBs) was developed, where K⁺-conducting membrane was used to segregate neutral-alkaline hybrid electrolytes and redox couples of Br₂/Br⁻and [Zn(OH)₄]²⁻/Zn at the positive and negative electrode. Benefited from an efficient and stable cathode catalyst (carbon-manganite nanoflakes), this AHZBB delivered a high average output voltage of 2.15 V and energy density of 276.7 Wh/kg without capacity attenuation after 200 cycles. More importantly, this work provides an efficient avenue to elevating the output voltage and energy density, and will strongly encourage studies on redox flow batteries.