Technology powered by lithium ion batteries
Swept up in the euphoria of a new phone, we often forget the impact of our obsession on the environment. The ever-increasing demand for technology is placing a strain on raw resources and creating a growing stockpile of e-waste.
Take lithium ion batteries (LIBs) for instance. LIBs power much of our daily lives. Everything from our mobile phones and handheld tools, to laptop computers and electric vehicles are driven by these powerhouse batteries. Without these modern energy storage devices, the way we stay in contact with friends, work and the world would drastically change.
Supercharged waste problem
The number of LIBs in Australia has grown by over 250 per cent in the last decade, driven largely by an increase in mobile phone usage. Over 5,300 tonnes of LIB waste is produced annually. And that number is growing. By 2036, it could exceed 600,000 tonnes each year.
As LIB use increases discussion then turns to what we do with all this battery waste.
Currently, there are three options for LIBs at the end of their life: landfill, burning, or recycling. While they can be recycled, most spent LIBs are either sent to landfill or incinerated. With more than 25 per cent of a LIB made up of heavy metal and five per cent a toxic electrolyte, none of these options are straight forward.
Burning the batteries produces numerous environmental and health hazards. It generates carbon dioxide, hydrogen fluoride and phosphoryl fluoride which can be dangerous to inhale.
Landfill also offers no long-term solution since LIBs eventually breakdown. Heavy metals and toxic electrolyte are released into the ground and work their way into the groundwater, contaminating our water supply. Any residual energy in waste batteries also has the potential to cause fires which can spread rapidly through the other flammable materials in landfill sites, causing even greater environmental damage.
Perhaps the best option is to recycle, yet only two per cent of LIBs disposed in Australia are recycled. Worldwide, the figure is not much better, with only five per cent recycled in the European Union and United States.
Wealth from waste
Avoiding the environmental, health and safety impacts of incinerating or disposing batteries in landfill, there is an additional economic opportunity in recycling spent LIBs.
Each tonne of battery waste has a recoverable value between $4,550 and $17,252 depending on the specific battery type<1>. With Australia producing over 5,300 tonnes of LIB waste annually that equate to a potential value of $24 to $91 million of recoverable materials each year.
By recycling materials that had previously been a part of our waste stream, Australians could create an innovative, sustainable industry by transforming this waste into wealth.
Closing the loop with battery recycling
Recycling LIBs is not a straightforward process. They contain many different materials, including plastics, metals like iron and aluminium, and electrodes that are comprised of complex compounds. Separating these materials during recycling is a challenge.
In Australia, most recyclers begin the process by pounding the batteries to dust. Next, they separate out the large aluminium and copper foils and throw away the plastic. The remaining powder is sent overseas for further processing.
Overseas, the valuable materials are recovered through two main techniques.
Pyrometallurgy is a thermal process that involves heating the powder to extract a mixture of nickel, cobalt and copper metals. Then the other technique, hydrometallurgy, uses chemical extraction methods to separate these metals from each other.
Lithium and other valuable materials are often left behind. However, pyrometallurgy and hydrometallurgy processes are beginning to be modified to recover lithium.
Leading the charge into new battery technology
A team of CSIRO researchers, led by Dr Anand Bhatt, are tackling the battery waste problem head on, developing new processes that will allow us to safely and effectively recycle LIBs right here in Australia.
Before they can be disposed of or recycled it is essential to completely discharge the batteries. Any residual energy stored within the battery presents a huge fire risk. Slight damage to the casing can create sparks and lead to a fire.
In July of this year alone, Queensland Fire and Emergency Services recorded three incidents where LIBs caused a fire.
Dr Bhatt and his team are developing new discharge technologies which make the transport and storage of LIBs significantly safer, greatly reducing the risk of fire.
“We have developed two different process depending on the size of the battery,” said Dr Bhatt.
“For small batteries, like those in your mobile phone, the energy is extracted through a wet discharge bath. For larger batteries, like those in an electric vehicle, the discharged energy is fed back into the grid and available for other uses.”
The team is also working on the techniques to recover lithium PF6 (LiPF6), a major component of the LIB electrolyte.
“Traditionally, the lithium recovered from LIBs is in the form of a simple salt,” said Dr Bhatt. “To reuse this in a new battery the salt needs to be chemically reacted back to LiPF6 in a process that is energy intensive and requires a range of toxic materials.”
Current processing technologies mean it is easier, less energy intensive and cheaper to produce the LiPF6 from raw materials than from the lithium recovered from waste batteries. Consequently, most of the recovered lithium is used as an additive in cement.
The new recycling process developed by CSIRO allows LiPF6 to be extracted directly and reused easily in the manufacture of new batteries. With no further processing required it saves energy and resources.
While these technologies are still under development, they provide a path forward in the development of sustainable recycling processes for LIBs right here in Australia. Being smarter about how we recover materials could open up a $4 billion on-shore recycling industry in Australia by 2040. By closing the loop on the battery lifecycle, we conserve resources, reduce our impact on the environment and balance our hunger for new tech.
For more information about emerging opportunities in battery technology, download the 2020 report: State of Play: Australia’s Battery Industries by Best, A. and Vernon, C. as at March 2020. CSIRO, Australia
<1> without considering the costs involved in recovery