In 2020, NTU used orange peel to recycle spent lithium-ion batteries; the process recovered about 90% of cobalt, lithium, nickel, and manganese from old cells

Could orange peels help recover metals from a spent cellphone battery? Researchers at Nanyang Technological University in Singapore tested just that in 2020, using discarded orange peels to recover valuable metals from spent lithium-ion batteries, instead of using traditional industrial chemicals. According to NTU's own research announcement, the team recovered close to 90 percent of the cobalt, lithium, nickel, and manganese from the dead cells. Every old cellphone, laptop, or electric vehicle battery in your drawer contains metals that were mined and processed at real environmental and financial cost. This research shows that those metals can be recovered and reused with the help of a common fruit.

Old batteries and America's critical minerals problem

Lithium-ion batteries power smartphones, laptops, light vehicles, and an increasing percentage of cars on American roads. All of these products eventually lose battery capacity, and when they do, the batteries must be disposed of properly. The United States Environmental Protection Agency states that most spent lithium-ion batteries are likely hazardous waste because of their ignitability and reactivity, and generators are responsible for managing them under federal hazardous waste requirements. According to the EPA's page on lithium-ion battery recycling, recycling these products helps satisfy the demand for critical minerals to manufacture modern electronics and battery vehicles. These metals include cobalt, lithium, nickel, and manganese, which the Federal Register's 2022 Final List of Critical Minerals names as essential materials, and a steady supply of which is necessary to maintain the country's economic and strategic security. This is why the NTU finding matters: it could help recover critical minerals from used batteries, reducing the need for new mining and proper disposal.


Turning orange peel into a battery recycling tool

Traditional battery recycling typically involves acid leaching and hydrogen peroxide as a reducing agent to remove heavy metals from spent battery components, according to the EPA. However, the research group of Professor Madhavi Srinivasan and Assistant Professor Dalton Tay at Nanyang Technological University (NTU) suggests a milder, more sustainable method that uses a familiar kitchen ingredient: orange peels. A study, "Repurposing of Fruit Peel Waste as a Green Reductant for Recycling of Spent Lithium-Ion Batteries," published in ACS Publications, efficiently extracts valuable metals from spent lithium-ion batteries. Specifically, the orange peel replaces hydrogen peroxide as the reducing agent; the process still relies on citric acid, a weak organic acid, to actually leach the metals out of the battery material.

Since orange peels are mostly cellulose, heating them converts some of the cellulose into sugars that help extract metals from spent lithium-ion batteries, according to NTU's article. Moreover, the peel's naturally present flavonoids and phenolic acids also contribute to the method's high efficiency, as the research team concluded. Indeed, the work shows that using orange peels can yield results comparable to the hydrogen peroxide process while being much milder than traditional recycling.

The lab results, without the hype

It's important to be clear about what exactly this research claims. In controlled lab experiments, the NTU team recovered nearly 90 percent of the cobalt, lithium, nickel, and manganese from spent cells using the orange peel process. The resulting solid residue was tested and found to be less hazardous, which the researchers considered a good sign that the process is environmentally friendly. These are the lab results, and while this process could be implemented in a commercial recycling plant in the United States, the study itself does not demonstrate that conclusion. What the study does demonstrate is a cheaper, less aggressive chemical process for extracting these metals from discarded batteries, using something normally thrown away as food waste. The process will likely require years of further research and testing before it can be used at full commercial scale.

Connecting fruit waste to the battery supply chain

Orange peel is a by-product of the juice and food industry; using it to recover metals from spent batteries is a clever way to connect two waste streams that would otherwise never meet. That's not the only reason that the work fits into a larger context. According to the U.S. Department of Energy's Critical Minerals and Materials page, one of its strategic pillars is to promote recycling and alternative uses.

Where orange peel battery recycling goes from here

What this research shows is that scientists are developing alternative ways to recover the same materials used in cell phones, laptops, and cars in the United States. The next spent battery may not simply be disposed of as waste. According to this study, some recoverable metals could be reintroduced using a less damaging technique. As battery-recycling infrastructure develops, methods like this could eventually give manufacturers a gentler alternative to hydrogen peroxide specifically, one piece of a larger recycling process that still depends on acid leaching.