Australia, Renewables, Storage

Food waste fules future batteries

Scientists at the University of New South Wales have developed a promising new component for batteries derived from common food acids like those found in fruits, wine, and sherbet.

The prototype lithium-ion battery anode replaces conventional graphite with metal compounds made from readily available acids like tartaric acid and malic acid.

According to lead researcher Professor Neeraj Sharma, this novel battery design increases energy storage capacity while reducing environmental impact across material sourcing and manufacturing processes.

“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 said.

Current graphite anodes require environmentally-damaging purification steps and are fundamentally limited in their storage capacity. In contrast, the food acid anodes are made through an aqueous process using non-toxic solvents. Their higher energy density could help meet rapidly growing battery demands for renewable energy storage.

“Using food acids to produce water-soluble metal dicarboxylates (electrode materials) presents a competitive alternative to graphite used in the majority of lithium-ion batteries that can, as we’ve demonstrated, optimise battery performance, renewability and cost to better support battery demand,” he said.

The key innovation stemmed from a first-year chemistry principle – that metals react with acids to produce salts. Sharma’s team recognised that these salt compounds surprisingly outperformed the original food acids in battery testing.

By strategically pairing metals like iron or zinc with fruit acids, they created optimised dicarboxylate salts for use as anodes.

Sharma’s solid state materials group is now scaling up production from coin cells to larger pouch cells. Upcoming work will evaluate cycle life and temperature performance to prove commercial viability. The researchers also plan to extend the technology to sodium-ion batteries.

Perhaps most promising is the potential to create anodes from various bio-waste streams diverted from landfills. Coffee grounds, fruit byproducts, and even spoiled wines could become sources of carbon and acids for battery manufacturing.

“There isn’t a single battery solution for all our needs,” Sharma said.

“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.”

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