A team of scientists from the Nanyang Technological University, Singapore (NTU Singapore), has devised a method for extracting and reusing precious metals from depleted lithium ion batteries using fruit peels.

The scientists demonstrated that a combination of ground-up overdried orange peel and citric acid from citrus fruits effectively recovered 90% of lithium, cobalt, manganese and nickel from depleted lithium ion batteries. The recovered materials, which were nontoxic, were then successfully used to develop new functional batteries.

According to the team, the key to successfully recovering those precious metals was the cellulose in the orange peel, which is converted into sugars when heated during the extraction process. The sugars reportedly encourage the metal recovery from the battery waste.

Current methods for recovering precious metals from depleted batteries tend to emit hazardous gases or produce secondary pollutants, which are unsafe for the environment. Likewise, current methods tend to be energy intensive.

As such, the method from NTU Singapore proposes to make the manufacture of batteries sustainable, helping to solve a growing global electronic waste (e-waste) issue, while also addressing the issue of food waste by repurposing fruit peels. The NTU Singapore team believes that other cellulose-rich fruit and vegetable waste could be used to recover precious metals in the future.

The research appears in the journal Environmental Sciences Technology.