A recent Stanford University study published in Nature Communications demonstrates that recycling batteries offers substantial environmental benefits, including significant reductions in greenhouse gas emissions, energy use, and water usage, compared to mining for new metals.
Stanford Assistant Professor William Tarpeh and Ph.D student Samantha Bunke in the Tarpeh lab. Image Credit: Bill Rivard/Precourt Institute for Energy
Recycling lithium-ion batteries to recover their critical metals has substantially less of an environmental impact than mining virgin metals. Recycling may, for the most part, alleviate the long-term supply insecurity of vital battery minerals, both physically and geopolitically.
Lithium-ion battery recyclers source materials from two main streams: defective scrap from battery manufacturers and “dead batteries,” primarily collected from workplaces. Lithium, nickel, cobalt, copper, manganese, and aluminum are extracted from these sources during recycling.
The study measured the environmental impact of this recycling process and discovered that it uses roughly one-fourth of the water and energy required to mine new metals and emits fewer than half the greenhouse gases (GHGs) of traditional mining and refinement of these metals.
The environmental benefits are even greater for the scrap stream, which makes up roughly 90% of the recycled supply under study. It accounts for 11% of energy use, 12% of water use, and 19% of mining and processing-related GHG emissions. Although not measured explicitly, lower energy consumption is also associated with lower levels of air pollutants such as sulfur and soot.
Recently, I was in an Uber electric vehicle. The driver asked me if EVs really are ‘good’ for the environment because he recently had read that maybe they aren’t. All he knew was that I was faculty at Stanford.
William Tarpeh, Assistant Professor and Study Senior Author, Chemical Engineering, School of Engineering, Stanford University
“I told him that EVs definitely are good for the environment, and we’re now finding new ways to make them even more so. This study, I think, tells us that we can design the future of battery recycling to optimize the environmental benefits. We can write the script,” said Tarpeh.
Location, Location
The location of the processing facility and the source of electricity significantly impact the environmental effects of battery recycling.
A battery recycling plant in regions that rely heavily on electricity generated by burning coal would see a diminished climate advantage.
Samantha Bunke, PhD Student and Study Lead Investigator, Stanford University
“On the other hand, fresh-water shortages in regions with cleaner electricity are a great concern,” added Bunke.
Redwood Materials in Nevada, North America's largest industrial-scale lithium-ion battery recycling facility, provided most of the study's battery recycling data. Redwood benefits from the cleaner energy mix in the western US, which consists of solar, geothermal, and hydropower.
Another important consideration is transportation. For instance, the Democratic Republic of the Congo is where 80% of the world's cobalt supply is mined and processed. Afterward, 75% of the cobalt used in batteries is transported to China for refinement via land, air, and sea. In the meantime, Australia and Chile mine most of the world's lithium supply. The majority of that supply also ends up in China. Gathering used batteries and scrap, which need to be delivered to the recycler, is the analogous procedure for battery recycling.
We determined that the total transport distance for conventional mining and refining of just the active metals in a battery averages about 35,000 miles (57,000 kilometers). That’s like going around the world one and a half times.
Michael Machala, Ph.D ’17, and Study Lead Author, Stanford University
“Our estimated total transport of used batteries from your cell phone or an EV to a hypothetical refinement facility in California was around 140 miles (225 km),” added Machala, who was a Postdoctoral Scholar at Stanford’s Precourt Institute for Energy at the time of research and is now a Staff Scientist for the Toyota Research Institute.
This distance was based on presumed optimal locations for future refining facilities amid ample US recyclable batteries.
Academia/Industry Cooperation
Based on information from an industrial-scale recycling facility, this study is the first lifecycle analysis of lithium-ion battery recycling that is known to exist.
“We are grateful for the data supplied by Redwood Materials from the largest industrial-scale lithium-ion battery recycling facility in North America, which was needed for this research,” said William Tarpeh.
Redwood was among the first to incorporate the project's lessons into their own operations and environmental impact; they have since started construction on a new facility in South Carolina.
“The insights of this research have played a key role in refining Redwood’s battery recycling processes,” said JB Straubel, Company Founder and Chief Executive. Straubel earned his undergraduate and graduate degrees from Stanford.
“Thanks to the researchers’ observations, we have further reduced our environmental footprint, while also advancing both resource efficiency and process scalability,” said Straubel.
Patent Advantage
The environmental results of Redwood do not accurately reflect the environmental performance of the fledgling battery recycling sector as a whole. A crucial step in the refining process, conventional pyrometallurgy uses a lot of energy and typically requires temperatures above 2,550 ℉ (1,400 ℃).
However, Redwood has patented a method known as "reductive calcination," which produces more lithium than traditional techniques, does not use fossil fuels, and requires much lower temperatures.
“Other pyrometallurgical processes similar to Redwood’s are emerging in labs that also operate at moderate temperatures and don’t burn fossil fuels,” said Xi Chen, the third lead author and Postdoctoral Scholar at Stanford during the time of research and now an Assistant Professor at the City University of Hong Kong.
“Every time we spoke about our research, companies would ask us questions and incorporate what we were finding into more efficient practices. This study can inform the scale-up of battery recycling companies, like the importance of picking good locations for new facilities. California doesn’t have a monopoly on aging lithium-ion batteries from cell phones and EVs,” added Chen.
Looking Ahead
Senior author Tarpeh says that although industrial-scale battery recycling is expanding, it is not happening fast enough.
“We’re forecast to run out of new cobalt, nickel, and lithium in the next decade. We’ll probably just mine lower-grade minerals for a while, but 2050 and the goals we have for that year are not far away,” said Tarpeh.
The United States has successfully recycled 99% of lead-acid batteries for decades but currently only recycles around 50% of lithium-ion batteries. According to Tarpeh, the opportunity is substantial because used lithium-ion batteries contain materials that have an economic value that is up to ten times higher.
“For a future with a greatly increased supply of used batteries, we need to design and prepare a recycling system today from collection to processing back into new batteries with minimal environmental impact. Hopefully, battery manufacturers will consider recyclability more in their future designs, too,” said Tarpeh.
Journal Reference:
Chen, X., et al. (2025) Life cycle comparison of industrial-scale lithium-ion battery recycling and mining supply chains. Nature Communications. doi.org/10.1038/s41467-025-56063-x