High Energy and High Power Electrically Rechargeable Zinc-Air Battery
High energy density zinc-air batteries are already on the market with energy densities above 400 Wh/kg but they are not rechargeable. The technology to make zinc-air batteries on an industrial scale therefore already exists. The challenge now is to be able to make zinc-air batteries rechargeable.
Attempts to develop such a battery have failed due to the poor reversibility of the air electrode and due to the formation of zinc dendrites during charge. By using 3D electrode structures and a protected air electrode, an electrically rechargeable zinc-air battery has been developed which has solved these problems and which has high cycle efficiencies.
One of the disadvantages of metal-air batteries is their poor discharge power performance compared to Lithium-ion batteries. The culprit is the air electrode, the zinc electrode is not limited on discharge. Oxygen reduction is a multi-electron reaction with slow kinetics. The reaction is further impaired by the low concentration of the active material (oxygen from the air) and the low molar density of a gaseous reactant.
The addition of a second high power cathode has solved this problem and has brought very interesting power and energy performances to our zinc-air battery.
High energy densities have also been achieved using zinc electrodes with very high loadings, up to 630 mAh/cm².
These zinc-air cells are tested under standard cycling conditions, but also using normalised electric vehicle driving cycles.