High performing electrically rechargeable zinc-air batteries for sustainable mid-term energy storage

Energy storage is critical for the EU energy system to reach a large renewable energy share, climate neutrality, and affordable energy costs. Currently available energy storage solutions suffer from limited storage time, the use of toxic/flammable components, large amounts of critical raw materials (CRMs), and high costs that limit their large market deployment. Metal-air batteries present several advantages like cheap and abundant active materials (e.g., zinc + air), and high gravimetric energy density together with long-term stability; but, even in its more mature configuration, they cannot guarantee storage times > 4-12 h, and the present mechanical recharging concepts drastically increase operation and maintenance costs. HIPERZAB will design and validate at lab scale, for the first time ever, an Electrically Rechargeable Zinc-Air Battery (ERZAB) to enable breakthroughs in cyclability, storage time, costs, and life cycle design ideal for mid-term storage (days/weeks) to be coupled with renewables and electrolysers. To reach this goal, HIPERZAB will develop three innovative components: (i) a 3D porous Zn/biopolymer composite anode, (ii) an eco-friendly bilayer gel electrolyte based on naturally occurring precursors, and (iii) a CRM-free cathode based on high entropy oxides (HEOs). These components will be integrated into a single device proposing a radically new battery design that enables the water/air management control during cycling and the durability/performance of materials and components. To shed light into the research challenges, HIPERZAB will further focus on unraveling the correlations between materials, operating conditions, and electrochemical phenomena upon cycling through operando characterisations and multiscale modelling. HIPERZAB's developments will be continuously guided by life cycle and circular economy approaches to ensure sustainable end-of-life options.m