Iwastheone shares a report from Ars Technica: Researchers from Carnegie Mellon University published a paper in Nature Sustainability this week that looks at the emissions and economic costs associated with recycling automotive batteries. They specifically addressed batteries with three types of cathode chemistry: nickel manganese cobalt oxide (NMC), nickel cobalt aluminum oxide (NCA), and iron phosphate (LFP). The first two cathode chemistries are common in passenger vehicles, and LFP is common in buses (bus maker BYD uses LFP batteries, for example). Since the packaging of batteries is important to the recycling method, cylindrical batteries (the types of cells that Tesla makes) are compared to pouch cell batteries in the analysis. The researchers also compared recycling methods. These include pyrometallurgical recycling (exposing the valuable parts of the battery to high temperatures and then recovering those metals as alloys), hydrometallurgical recycling (leaching valuable metals from batteries and separating the desired metals from the resulting solution), and “direct cathode recycling,” where the battery’s cathode is retained as-is, but new lithium is added in such a way that the battery regains its original performance.
Ultimately, LFP-cathode batteries were not able to avoid additional emissions under any recycling circumstances. The iron materials used in those bus batteries are already efficient to mine, the paper notes. This results “in a smaller GHG [greenhouse gas] emissions offset from the recovered materials that is insufficient to offset the energy and GHG emissions associated with the recycling processes considered.” For now, new bus batteries seem to be cheaper and better for the environment than recycled bus batteries. The story is more complicated for electric passenger vehicle batteries, however. For both NMC and NCA cells, hydrometallurgical and direct cathode removal recycling methods do result in a reduction of GHG emissions, but only recycling via direct cathode removal with pouch cells shows a statistically significant reduction in emissions.
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