How battery recycling works

Batteries are unique from other energy sources, like fossil fuels, because they are infinitely recyclable. The critical minerals used to make batteries remain fully intact when the battery dies, and these metals can then be recycled into new battery materials, creating a circular battery supply chain. 

Yet, questions often arise about recycling: What happens to batteries when they are sent for recycling? Are they actually recycled, or do they end up in landfills or overseas? Is recycled content effective? Misconceptions can create confusion, making it essential to understand the different recycling methods and what really happens when you recycle an old battery. 

Redwood’s battery recycling process 

At Redwood, we’ve designed our recycling process for maximum efficiency, sustainability, and recovery. Our recycling operations use the residual energy in end-of-life batteries to power the process. By leveraging advanced techniques that integrate mechanical shredding, chemical extraction, and purification, we can recover more than 95% of the critical elements found in batteries, including lithium, cobalt, nickel, and copper. This approach minimizes waste and energy use, while ensuring that no valuable material is lost.  

Our process also utilizes highly energy-efficient technology powered entirely by renewable energy, with no waste streams or wastewater. Materials that cannot be directly reused in battery manufacturing are recovered for other industrial applications—such as gypsum for drywall and graphite for industrial lubricants. Our operations are 100% electrically powered too, relying solely on clean energy without using natural gas or other fossil fuels. With zero liquid discharge, we eliminate the risk of contaminated process water leaving the site. 

To quantify the environmental footprint of our process, we engaged a cross-disciplinary team of engineering professors and graduate students from Stanford University. Their analysis produced an objective life cycle assessment (LCA), benchmarking our process against mining and providing an open-source model to support our ongoing innovation and scaling efforts. Compared to traditional methods of processing mined ore into battery-grade materials, our process uses 80% less energy, reduces CO₂ emissions by 70%, and requires 80% less water. Our processes also achieve at least 40% lower emissions than other recycling techniques. 

Building a circular future

Redwood’s recycling process doesn’t just recover metals—we will also produce highly refined, battery-ready materials, including cathode active material, that can go directly back into cell production. By supplying these critical materials to manufacturers, we are closing the loop on the battery supply chain, reducing dependence on newly mined resources, and significantly lowering the environmental impact of battery production. In 2024 alone, Redwood recycled and returned enough material to the supply chain to build 1.5 billion new phones—paving the way for a truly circular and sustainable battery industry.