The invention enables electrical recharging in metal-air batteries, which is demonstrated for a zinc-air battery. It decouples the two reactions at the electrodes by introducing a third redox reaction, ensuring that metal oxidations take place in an aprotic solvent and oxygen reduction takes place in water. Two reversible electrodes, called auxiliary electrodes, are used in each part of the cell, one with the metal electrode in an aprotic medium (metal-ion cell) and the other with the air cathode in water (air cell). The four redox reactions that take place, in the case of a zinc-air battery, while discharging are all reversible reactions which are reversed when current is passed in a reverse direction.
Figure (1) Image of the prototype setup; (2) Graph showing the voltage variation at different current levels
Metal-air batteries are devices that produce current by oxidizing metal at the negative electrode and reducing the oxygen in the air at the positive electrode. The electrolyte medium is also selected based on the metal used. Such batteries however, are difficult to recharge simply by reversing the current through them.
Metals using organic solvents face poor life cycle and low efficiency issues. Metals compatible with water are limited by its electrochemical window. Even zinc-air batteries, which can be recharged natively, have issues recharging due to parasitic reactions and oxide depositions. Thus, there is a need for a reliable method to charge a metal-air cell using electricity.
- Different medium for each electrode: usage of separate aprotic/water medium for each electrode reduces parasitic reaction and ensures reversibility of reactions
- Increased capacity of the cell: by using certain variations of the auxiliary electrodes, the capacity of the cell can be increased
- Increased cell efficiency: the separation of the anode and cathode cells makes individual tuning of electrolytes to the anode/cathode possible
- Applicable to other alkali/alkaline earth/transition metals-air batteries.
- The metal air battery contains two reversible electrodes (auxiliary electrodes) which are electrically connected to each other.
- In the present work, the concept is demonstrated using CuFe(CN) 6 and NiFe(CN) 6 auxiliary electrodes with a zinc-air battery
- One is placed in an aprotic electrolyte with the metal electrode (metal-ion cell)
- The other is placed in the aqueous electrolyte along with air cathode (air cell)
- For metal-ion cell, zinc perchlorate in acetonitrile is used as electrolyte media
- For air cell, zinc sulphate along with sulfuric acid in water is used as electrolyte
- Air cathode active material is platinum on carbon (20 w/w%)
- The metal anode and air cathode as positive terminal are connected to external load
- The auxiliary electrodes will undergo an electrochemical reaction in such a way that the ionic balance is maintained in both the cells
- This is a reversible reaction which can recharge the battery by reversing the current
The technology has been granted a patent and is currently available for licensing.
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The rechargeable metal-air battery technology promotes cleaner energy alternatives by reducing reliance on fossil fuels. It improves the reusability and sustainability of energy storage systems, supporting long-term environmental goals. It enables efficient storage for renewable energy applications, enhancing energy access in off-grid areas. Additionally, it supports the transition to low-emission transport and grid solutions, helping address climate change and energy equity.
- Transportation
- Household storage
- Grid level storage
- Portable electrical devices
- Stationary energy storage systems
Geography of IP
Type of IP
202021043461
512412