Repurposing fruit peel waste to recover precious metals from old lithium-ion batteries could help ‘close the loop’ and facilitate a more circular battery market.
That’s the suggestion from Professor Madhavi Srinivasan, Co-Director of the NTU Singapore – CEA Alliance for Research in Circular Economy and Assistant Professor of the NTU School of Materials Science and Engineering and School of Biological Sciences Dalton Tay, who spoke to FNZ about their research that used orange peel waste to extract and reuse spent batteries: “The key lies in the cellulose found in orange peel, which is converted into sugars under heating conditions during the extraction process. These sugars converted to glycose enhance the recovery of metals from battery waste.”
Spent batteries are conventionally treated with temperatures of more than 500°C to smelt valuable metals, a process which emits hazardous toxic gases – other alternative approaches that use acid solutions or hydrogen peroxide to extract metals are being explored but they still produce secondary pollutants that pose health and safety risks.
However, the novel fruit peel approach, which is based on a green chemical concoction that consists of orange peels and citric acid, cleanly extracted around 90% of cobalt, lithium, nickel and manganese from old lithium-ion batteries.
The recovered batteries have also a charging capacity comparable to commercial lithium-ion batteries.
They note: “Electronic waste is increasing and the majority of lithium-ion batteries end up in landfill with toxic elements being discarded on the soil.
“This method offers a sustainable way to tackle the problem of electronic and food waste as well as the resource depletion by keeping these precious metals in use as much as possible.”
Around 1.3 billion tonnes of food waste and 50 million tonnes of e-waste are generated globally every year, according to the Food and Agriculture Organization (FAO) of the United Nations and a report from the Platform for Accelerating the Circular Economy (PACE) and the UN E-Waste Coalition.