A research team from the University of NSW is looking at diverting bio-waste such as coffee grounds from landfill to use them as sources to formulate new electrode microstructures for next-generation batteries.
A novel battery component that uses food-based acids found in sherbet and winemaking could make lithium-ion batteries more efficient, affordable and sustainable.
The prototype, developed and patented by UNSW chemists, reduces environmental impacts across its materials and processing inputs while increasing energy storage capability.
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The single-layer pouch cell currently being optimised is similar to what you’d use in a mobile phone, only smaller, says lead researcher Professor Neeraj Sharma, who leads the solid state and materials chemistry group at UNSW Science.
“We’ve developed an electrode that can significantly increase the energy storage capability of lithium-ion batteries by replacing graphite with compounds derived from food acids, such as tartaric acid [that occurs naturally in many fruits] and malic acid [found in some fruits and wine extracts],” he explains.
Food acids are readily available, typically less aggressive and contain the necessary functional groups or chemical characteristics.
“[Our battery component] could potentially use food acids from food waste streams, [reducing their environmental and economic impact]. Its processing uses water rather toxic solvents, so we’re improving the status quo across multiple areas,” Prof Sharma says.
The team has worked with Prof Veena Sahajwalla to pyrolyse coffee grounds to use them as a carbon source to make anodes within lithium-sulphur batteries,.
More than eight million tons of waste coffee grounds enter landfill globally every year. Variations in quality caused by the supply chain, however, could affect consistency in energy storage capacity and safety aspects through unwanted side reactions, Prof Sharma says.
“We’re working to identify what sort of variability a battery can handle.”
The end-of-life cycle for batteries—how they degrade, safety and sustainability considerations—is also a significant concern.
“Recycling is a really big challenge here. In 10-20 years, we’re going to have a huge amount of the batteries from electric vehicles, scooters, power tools, and household and grid storage possibly coming offline.”
While some could potentially be repurposed as household, building or grid energy storage, many will need to be recycled, Prof. Sharma says.
“At the moment, the [associated recycling] process is very energy-intensive, using harsh chemicals.”
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There isn’t a single battery solution for all our needs, Prof. Sharma says.
“It’s about having different battery technologies for different applications, including bringing solar and battery power together in one device.
“And asking how we can input more sustainable processes, use more sustainable materials to make it cheaper, better, faster, safer.”
