Romania zinc-bromine flow energy storage battery project

Zinc-bromine flow batteries (ZBFBs) offer great potential for large-scale energy storage owing to the inherent high energy density and low cost. However, practical applications of this technology are hindered by low power density and short cycle life, mainly due to large polarization and non-uniform zinc deposition.

In particular, zinc-bromine flow batteries (ZBFBs) have attracted considerable interest due to the high theoretical energy density of up to 440 Wh kg−1 and use of low-cost and abundant active materials [10, 11].

Gao et al. demonstrated a zinc bromine static battery with a glass fibre membrane as the separator to control the self-discharge and improve the energy efficiency (Figure 10). This static battery was achieved by using tetrapropylammonium bromide (TPABr) as the complexing agent.

Lee et al. demonstrated a non-flow zinc bromine battery without a membrane. The nitrogen (N)-doped microporous graphene felt (NGF) was used as the positive electrode (Figure 11A,B).

The ZBFB delivers a peak power density of 1.363 W cm −2 at room temperature. The ZBFB stably runs over 1200 cycles (∼710 h) at 200 mA cm −2 and 60 mAh cm −2. Zinc-bromine flow batteries (ZBFBs) offer great potential for large-scale energy storage owing to the inherent high energy density and low cost.

The microporous separator also reduces the Br 2 passage to the anode to avoid direct chemical interaction with the anode and associated self-discharge. The basic electrochemical reactions of the zinc bromine battery can be simply represented as follows (reactions 1–5).