Researchers at Australia’s Edith Cowan University have redesigned zinc-air batteries by using a combination of new materials, such as carbon, cheaper iron and cobalt-based minerals.
In a paper published in the journal EcoMat, the scientists say that the new design has been so efficient it suppressed the internal resistance of batteries.
The device’s voltage was also close to the theoretical voltage which resulted in a high-peak power density and ultra-long stability.
“In addition to revolutionizing the energy storage industry, this breakthrough contributes significantly to building a sustainable society, reducing our reliance on fossil fuels, and mitigating environmental impacts,” lead researcher Muhammad Rizwan Azhar said in a media statement. “Using natural resources, such as zinc from Australia and air, further enhances the cost-effectiveness and viability of these innovative zinc-air batteries for the future.”
Azhar explained that a zinc–air battery consists of a zinc-negative electrode and an air-positive electrode.
Prior to this recent development, the main drawbacks of these devices were their limited power output due to the poor performance of air electrodes and their short lifespan.
With these issues being addressed, Azhar believes rechargeable zinc-air batteries can become more appealing for the storage of clean energy, particularly taking into account their low cost, environmental friendliness, high theoretical energy density, and inherent safety.
Zinc8’s proposal
Zinc8 proposes a battery or modular storage system designed to deliver power in the range of 20kW – 50MW with a capacity of eight hours of storage duration or higher.
In this battery, energy is stored in the form of zinc particles, similar in size to grains of sand. When the system is delivering power, the zinc particles are combined with oxygen drawn from the surrounding air. When the system is recharging, zinc particles are regenerated, and oxygen is returned to the surrounding air.
To get started, the system takes power from the grid or a renewable source and uses it to generate the zinc particles in a section called the ‘zinc regenerator.’
The zinc regenerator consists of two electrodes. During recharge, the regenerator undergoes an electrolysis process in which an external electrical load is applied to energize one particular electrode on which zinc is deposited. Simultaneously, oxygen evolves from the other electrode. Subsequently, a proprietary method is used to remove zinc from the electrode and transfer it to a fuel storage tank.
When the zinc particles stored in the tank are required -because power is needed-, they are delivered to the ‘power stack,’ where they are recombined with oxygen to generate electricity. The zinc oxide (ZnO) by-product is returned to the storage tank for later regeneration. Thus, there is no net consumption of zinc.