Recycling lead-acid batteries is easy. Why is lithium-ion battery recycling difficult?

The lithium-ion batteries in today’s electric vehicles are superior to the older lead-acid batteries in almost every way except one. Lead-acid batteries are still the most recycled product in the world.

Although lithium-ion batteries are designed to lead the clean energy transition, more than 100 million lead-acid batteries are still sold each year in the United States, mostly as starter batteries for cars, trucks, and boats.

When these lead-acid batteries discharge, almost all of them end up being recycled. In fact, the lead-acid battery industry claims a domestic recycling rate of 99 percent. In 2021, the US produced nearly one million metric tons of recycled lead. Almost all of the recycled lead was used to make new batteries.

Interestingly, none of this is actually new. Lead-acid batteries have been recycled since the 1920s. As early as 1930, the industry described battery lead as a “loan” rather than a form of “consumption.” By the 1960s, hundreds of small lead refineries were operating in and around US cities, making it an early form of urban mining.

These urban lead recycling operations were also a significant source of pollution. One of the earliest lead poisoning epidemics was associated with battery recycling operations in Baltimore, Maryland in the 1930s. In some places, recycling sites for abandoned lead-acid batteries can still be identified by elevated levels of heavy metals in the soil.

However, in the 1980s, the industry went through a major restructuring. New environmental laws have forced refiners to increase pollution controls. In response, many small processors closed. Those that remain have consolidated operations into integrated battery recycling operations with improved pollution controls. Today, a dozen highly regulated secondary lead smelters recycle the vast majority of used lead-acid batteries in the US.

With global production of lithium-ion batteries now overtaking lead-acid batteries, it is worth asking why lead-acid batteries have been recycled for so long and so efficiently, and what lessons this holds for closing the lithium-ion battery cycle. Consider these three points:

First, the chemistry and format of lead-acid batteries is highly standardized, which simplifies recycling. Unlike lithium-ion batteries, which come in different chemistries and shapes (cylindrical, flat, pouch, etc.), the relative uniformity of spent lead-acid batteries reduces the need to sort spent lead-acid batteries by chemical composition, shape, or size. This facilitates mass processing.

Second, the metal content of lead-acid batteries consists almost entirely of metallic lead and lead oxide paste—both of which are typically recovered in a pyrometallurgical recycling process at temperatures in excess of 2,000 degrees Fahrenheit. After processing, recovered lead is both functionally equivalent and cost competitive with lead obtained from primary ore.

In comparison, lithium-ion batteries are much more complex in material terms. This requires adapting lithium ion recycling processes to recover a range of cathode materials (lithium, cobalt, nickel, manganese, iron, etc.), anode materials (graphite) and conductors (aluminum and copper). These complexities pose serious challenges to the efficient recovery of materials and their cost-effective processing for reuse.

Third, beginning in the 1980s, the federal government and states banned the disposal of lead-acid batteries because of the high toxicity of lead. Although some spent lead-acid batteries are sent overseas for recycling, most are recycled domestically. (Concerns have been raised about the supply of used batteries to less well-regulated facilities in Mexico.) This means that recycling has played an important role in ensuring that the United States has an abundant and reliable source of domestic lead.

Looking ahead, the scale of lithium-ion battery recycling will expand rapidly. Large volumes of spent large-format electric vehicle batteries promise to drive the economies of scale needed to close the lithium-ion battery cycle. Studies show that recycling could reduce the combined demand for lithium, cobalt and nickel needed to electrify the transport sector by up to 30 percent between 2020 and 2050.

Expanding lithium-ion battery recycling will also create opportunities to improve the sustainability of recycling operations. Existing pyrometallurgical processes for lithium-ion batteries often recover only a fraction of the metal content of spent batteries (usually due to the cost of cobalt). Direct recycling strategies, such as those being explored at Argonne National Laboratory ReCell Centerhave the potential to significantly improve material recovery and reduce energy consumption and potential pollutants from lithium-ion battery recycling.

While private sector and government initiatives to promote recycling are growing in the United States, the flow of used lithium-ion batteries and the resources they contain can easily be diverted overseas. In the long term, a robust US lithium-ion battery recycling industry can play an important role in domestically sourcing advanced battery materials. Although its importance is little appreciated, it is precisely this role that the lead recycling industry has played in supporting domestic production of lead-acid batteries since the mid-twentieth century.

This post is adapted from the forthcoming book by James Morton Turner, Charged: The history of batteries and lessons for a clean energy future (August 2022). You can learn more about Charged in Turner tweets @_jay_turnthere is


Appreciate CleanTechnica’s originality and clean tech news coverage? Consider becoming a CleanTechnica member, supporter, technician, or ambassador — or a patron on Patreon.


Have a tip for CleanTechnica, want to advertise, or suggest a guest for our CleanTech Talk podcast? Contact us here.


Leave a Reply

Your email address will not be published. Required fields are marked *