Batteries for the future

In a speech delivered at the Australian Energy & Battery Storage Conference in Sydney earlier this year, Tim Jordan, Commissioner of the Australian Energy Market, highlighted one of the major challenges confronting Australia as the country transitions to a renewable energy future.  

“By AEMO’s current calculations…61 GW of storage capacity is needed by 2050”, he said “That’s 17 times current levels.”  

He went on: “And we could need even more storage. The more we electrify our homes, our businesses, our heavy industry and our transport, the more renewables and storage we will need.”  

Batteries will play a key role in solving the challenge of energy storage in Australia in the future, just as they have done so for humans around the world for centuries.  

The earliest example of a battery is the “Baghdad Battery”. Dated to around 250BC, it comprised a ceramic pot, tube of copper, and a rod of iron, and although its exact function in Mesopotamia remains unclear, replicas have shown it was capable of conducting an electric current.  

The first true battery was invented in 1800 by Italian physicist Alessandro Volta, who stacked discs of copper and zinc separated by cloth soaked in salty water. He then connected either end of the stack with wires, which produced a continuous electric current.  

The more we electrify our homes, our businesses, our heavy industry and our transport, the more renewables and storage we will need.

Tim Jordan

Nearly 60 years later, French physicist Gaston Plante invented the lead acid battery, which is the oldest example of a rechargeable battery. Then, in 1991, there was another huge breakthrough when Sony introduced the world’s very first commercial rechargeable, lithium-ion battery, following pioneering research by Professor Michel Armand – recognised as one of the “forefathers of modern batteries”.  

In the years since, lithium-ion batteries have revolutionised our lives. They are composed of an anode, cathode, separator, and a liquid electrolyte which fills the remaining space. The lithium is stored in the anode and cathode. During discharging, the anode releases lithium ions, which travel through a liquid electrolyte solution to the cathode. This process generates an electric current that powers whatever device the battery is linked to.  

During charging, the opposite occurs: lithium ions are released by the cathode and flow back to the anode.  

According to Professor Shirley Mang, professor of molecular engineering at the Pritzker School of Molecular Engineering at the University of Chicago, there are a number of advantages to lithium-ion batteries compared to other currently available rechargeable battery technologies like lead acid.  

As well as being “almost maintenance free”, they have a huge scaling ability and one of the highest energy densities of any commercial battery technology – nearly 300 watt-hours per kilogram. Equally importantly, “they have been getting cheaper and have a very long life”.  

This is primarily why, Meng says, lithium-ion is the most common battery chemistry used to not only store electricity in mobile phones, electric vehicles, and homes, but also in grid-scale applications. Indeed, most of the big batteries that already exist in Australia like the 300MW Victorian Big Battery at the Moorabool Terminal Station, just outside Geelong, are lithium-ion based.  

The same is true for big battery projects that are in the pipeline.  

For example, in March this year oil giant Shell announced that it had teamed up with the Green Investment Group to build the 200MW Rangebank lithium-ion battery in the Rangebank business park in Melbourne’s south-east. Five months earlier, Shell also announced plans to jointly develop with Ampyr Energy a 500MW lithium-ion battery in Wellington, New South Wales.  

But Meng says there are also a number of downsides to lithium-ion batteries, regardless of their size, which will become more acute as demand increases. For example, many of the critical elements that are needed to make them, like nickel, cobalt and copper are “in short supply.” As a result, Meng says the cost of lithium-ion batteries will soon “plateau”.  

“In fact, this year is the first time we have seen the cost of batteries increase because those elements are not widely available.”  

In addition, one kilowatt hour of lithium-ion batteries takes roughly 50 to 60 kilowatt hours to produce – but “lots of these batteries are currently being made by non-green electrons”, meaning their carbon footprint is “less than ideal”.  

Aside from these sustainability problems, the performance of lithium-ion batteries can also be impacted by extreme temperatures. As a result, they often need to be refrigerated to regulate their temperature – which, as Meng points out, “consumes valuable energy and compromises efficiency”.  

Furthermore, the liquid electrolyte used inside them is highly flammable – a risk that was recently highlighted by reports that a big battery caught fire in Queensland. This also means that lithium-ion batteries can be difficult to recycle. Indeed, Meng says that less than 20% of the lithium-ion batteries are recycled today. 

Despite these shortcomings, Meng believes lithium-ion batteries will continue to play a critical role moving forward in the energy transition. But she also believes we need to develop alternative types of batteries that will help us transition to a fully green renewable future.   

This year is the first time we have seen the cost of batteries increase because those elements are not widely available.”

Shirley Meng

Solid-state batteries are one alternative that she believes holds great promise. These batteries use solid electrolytes, rather than liquid ones, which gives them a higher energy density and also eliminates the risk of explosion or fire. In addition, they also perform better in extreme temperatures and because they are not made of a liquid, could also act as a structural feature in buildings.  

“Look at the wall behind you – any of the bricks could be solid-state batteries,” she says. “The dream is to make batteries multifunctional.”  

One problem with solid-state batteries, however, is that they are costlier to produce – at least at the moment.  

For more than a decade, Meng has also been championing sodium-ion batteries. These are similar to lithium-ion batteries in their construction, except they use sodium as their charge carrier.  

And although sodium-ion batteries have a smaller energy density than their lithium counterparts, Meng believes what they offer will still be sufficient for a lot of people’s energy needs. More importantly, she says, the main material needed for these batteries is found on Earth in abundance, making them a much more sustainable option.  

“If we use sodium, we don’t use lithium, we don’t need cobalt, and we don’t even use copper in the batteries. We eliminate many critical elements from the battery.”  

In order to develop what Meng describes as a “healthy battery industry” – in Australia and around the world – she emphasises the importance of not relying on one kind of battery.  

“Each country has its own unique energy needs – and therefore will require different types of batteries. Try to look for solutions that are best for your own country’s well-being. One battery is never going to solve every society’s problems. 

“And when we diversify the products, we reduce supply chain issues. There were wars to get oil. We really don’t want wars to happen to get the elements needed to make batteries.”