Which Metals From Spent Batteries Are Most At Risk Of Being Lost (not recovered) In Current Recycling Processes — And Why

When a lithium-ion battery reaches end of life, most of us imagine a tidy, industrial process that turns dead cells back into shiny metals for new batteries. The reality is messier. Batteries contain a mix of valuable transition metals, light elements, polymers, electrolytes and coatings — and the path from a shredded pack to saleable nickel or cobalt salts is full of opportunities for material to be lost. This article explains which metals are most at risk of being lost, why those losses happen, and what practical changes (in design, logistics and processing) can reduce losses and increase the fraction of materials that return to the supply chain.

Quick answer up front

If you want a fast answer: lithium and graphite (the light elements) are the most frequently lost or incompletely recovered in many current recycling flows, especially where pyrometallurgical processes or mixed shredding are used. Organics (electrolytes, binders) and light elements tied up in polymer or slag fractions are also commonly lost or burned. Copper and aluminum are typically recovered reasonably well; cobalt and nickel tend to be recovered at high rates in hydrometallurgical systems, but recovery depends on sorting and process choice. The risk profile varies by chemistry and by whether a plant uses pyro, hydro, or direct recycling — and the devil is in the feedstock and pretreatment details.

A short guide to the metals inside batteries and why they matter

Batteries contain two broad material classes: valuable transition metals used in cathodes (nickel, cobalt, manganese, sometimes iron or aluminum) and the conductive/structural metals used as current collectors and casings (copper, aluminum, steel). Anodes are primarily graphite (carbon) and increasingly silicon blends. Lithium is the light-but-critical element that enables electrochemistry. In addition there are electrolytes (organic solvents and salts), separators (polymers), and binders. Economically, cobalt and nickel have historically been the “money” metals that justify recycling, but as chemistries shift and lithium becomes more precious, attention is moving toward recovering lithium and carbon too.

Overview of common recycling routes and how they affect losses

There are three broad types of industrial recycling:

Hydrometallurgy: wet-chemistry leaching and separation to produce metal salts. This method is selective and can recover lithium, nickel, cobalt and manganese with good yields when feed is sorted and pretreatment is good.

Pyrometallurgy: high-temperature smelting that produces metal alloys, with some elements partitioning to slag. Robust to mixed feed, but lithium often ends up in slag and is harder to recover without downstream hydro steps.

Direct (closed-loop) recycling: aims to recover and repair cathode active materials with minimal chemical breakdown. Very efficient in theory, but highly sensitive to feed purity and cell construction.

Each route creates different loss modes. Pyro tends to lose light elements (lithium) to slag; hydro can lose small fractions through leach inefficiency and wastewater streams; direct recycling can lose material via contamination and inefficient delamination.

Where in the flow materials get lost — a process map

Losses occur at predictable stages: collection and handling (the wrong batteries dumped or damaged), disassembly (cells punctured or contaminated), mechanical pretreatment (shredding fines becoming airborne or lost to dust collection), thermal steps (volatilization and oxidation of organics and some salts), aqueous chemistry (dissolved metals in tail solutions), and final purification (trace contamination that makes a recovered salt off-spec and unsellable). Understanding these stages helps us identify which metals are vulnerable and why.

Lithium — the most frequently cited “at-risk” metal

Lithium is often the metal people worry about most when discussing losses. Why? Because lithium is relatively light, occurs at low mass fractions compared with transition metals, and has a chemical behavior that makes it easy to end up distributed in non-saleable streams. In pyrometallurgical processes, lithium tends to migrate into the glassy slag phase rather than the metallic alloy, which makes direct recovery from the smelter output difficult.

Recovering lithium from slag requires additional hydrometallurgical processing, which many operations don’t do unless economics justify it. In hydrometallurgical circuits, lithium is soluble — which is good — but it can remain in dilute solutions or be lost in wastewater if purification steps are incomplete. That combination of partitioning to slag or to dilute aqueous streams makes lithium comparatively more at risk than nickel or cobalt in some existing plants.

Graphite and carbon — the anode materials that disappear

Graphite is abundant in every lithium-ion cell and represents a large fraction of mass. Recovering graphite at battery-grade quality is technically challenging: it must have the right particle morphology, graphitic order, and surface chemistry. Mechanical shredding and high-temperature treatments can damage graphite particles and oxidize carbon, turning them into low-value fines or gaseous CO/CO₂. Hydrometallurgical methods can recover carbon as solids, but the purity and morphology often fall short of battery-grade requirements. In practice, a lot of graphite ends up as low-grade carbon or is lost in sludges, so graphite recovery rates for battery-grade reuse are generally lower than for transition metals — and that’s a major circularity blind spot.

Cobalt and nickel — valuable and usually well recovered, but not guaranteed

Cobalt and nickel are typically the “easier” metals to recover, especially by hydrometallurgy. These metals dissolve under common leach chemistries and can be selectively precipitated or solvent-extracted with high efficiencies. That’s why many commercial systems focus on them: the economics support the chemical effort. However, their recovery rates are still dependent on feed quality and pretreatment. If feedstocks are contaminated with copper, aluminum, or organics, separation becomes harder and extra steps may be needed. Also, as battery chemistries trend toward lower cobalt content, the economic buffer that made cobalt a cash driver shrinks, meaning plants must be more efficient in recovering nickel and lithium to remain profitable.

Manganese and iron — lower-value but susceptible to losses in mixed processes

Manganese and iron are commonly used in certain cathodes (LMO, LFP, NMC blends). Their economic value per kg is lower than nickel or cobalt, and in some pyrometallurgical flows manganese can partition unpredictably between alloy and slag phases. In hydrometallurgy manganese is usually soluble and recoverable, but if purification is not prioritized, some manganese can be left in intermediate streams or rejected as lower-value sludge. Iron, as in LFP chemistries, is abundant but not high-value, so some recyclers deprioritize intensive purification, which leads to lower “recovery of value” even when mass is technically captured.

Copper and aluminum — collectors that are usually recovered but can contaminate streams

Copper and aluminum are the workhorse metals in cells (current collectors, busbars, casings). They’re relatively easy to recover mechanically and metallurgically: magnets, eddy-current separators, and standard electrowinning or smelting processes handle them well. However, if shredding creates fine mixed powders of active material, foil and binder, copper and aluminum fragments can contaminate the active material fraction, making subsequent direct-regeneration or chemical-processing steps harder. In some shredding-heavy workflows, copper and aluminum end up in metal fractions and are recovered cheaply, but the cost of separating them from active powders can reduce yield of battery-grade materials.

The electrolyte, fluorine and elemental halogens — chemically mobile and problematic

Electrolyte salts (e.g., LiPF₆) and their decomposition products often contain fluorine and phosphorus. During thermal processing or shredding, these compounds can hydrolyze and generate hazardous fluorinated organics or HF if water is present. Fluorine doesn’t map cleanly to a metal to recover — it creates environmental liabilities and corrosion that can hinder metal recovery and damage equipment. Removing fluoride and similar anions from aqueous streams is costly, and losses of lithium tied up in fluorinated complexes can occur if purification isn’t thorough. So while fluoride itself is not a metal, it affects recovery economics and increases the chance of losing lithium.

Precious metals in electronics — usually well recovered when electronics are processed cleanly

Gold, palladium, and other precious metals are common in electronic boards and connectors. When electronics are properly separated and processed, these metals can be recovered with high yields because established precious-metal recovery technologies are mature and profitable. The real risk is that precious metals are missed when printed circuit boards are shredded along with batteries or when informal burning destroys organics but scatters fines. In properly run urban-mining facilities, precious metals are typically not the most at-risk fraction.

Rare and trace metals — easy to overlook and hard to reclaim

A variety of trace elements (e.g., vanadium, titanium, rare earths in some batteries or associated electronics) may be present at low concentrations. These are often not economical to isolate in mainstream recycling flows and may be diluted among sludges, slags or dusts. Because they occur at low mass fractions and their market value is tied to purity, trace metals are more likely to be lost unless a plant specifically targets them or a regulatory framework requires capture.

How shredding and mechanical pretreatment contribute to losses

Mechanical pretreatment — shredding, crushing, sieving — is a necessary step for many flows. But it creates fines, aerosols and mixed slurries that are tricky to handle. Very fine particles of active material may be carried away in dust collectors or end up in wastewater during wet processing. Those fine particles are hard to re-incorporate into battery-grade materials and are often destined for lower-value uses or disposal. Additionally, shredding can rupture cells and volatilize some components, increasing the risk of losing lithium and organics.

Thermal losses: volatilization and oxidation at high temperatures

High-temperature steps can change the fate of certain elements. Organics combust and convert to gases, carbon oxidizes to CO₂, and volatile salts can evaporate or react to form refractory phases. Lithium salts can react into glassy or ceramic slags that are stable but not easily processed. If a plant prioritizes throughput over careful material capture, thermal losses increase — especially for lithium and organics.

Aqueous losses: dissolved metals in wastewater and tail streams

Hydrometallurgical operations rely on leaching metals into solution. But any aqueous stage carries the risk that metals will end up in dilute streams that are costly to process to recovery-grade purity. Wastewater treatment and solvent-extraction systems can recover much of the dissolved metals, but process inefficiencies or poor reagent recovery can leave valuable metals in tailings or effluent. The smaller the metal fraction (e.g., lithium), the greater the relative impact of these losses.

Contamination and mixing — how impurities reduce saleable yields

Sometimes materials are not “lost” in the physical sense but become contaminated to the point of being unsellable for battery manufacture. Trace levels of chloride, fluorine, copper in cathode powders or residual binders can be showstoppers. Reprocessing contaminated streams is costly; many plants instead sell contaminated outputs at a discount as lower-grade commodities, effectively “losing” the battery-grade value of those metals.

Why feedstock heterogeneity increases risk

If a recycling plant receives mixed chemistries and battery formats without reliable sorting, it must rely on generic shredding and broad recovery methods. Heterogeneous feed increases the chance that certain metals (especially lithium) will partition unpredictably between fractions, and that contaminants will reduce the marketability of recovered materials. Sorting by chemistry and format upstream is therefore crucial to reducing metal loss.

Safety-first choices that unintentionally increase losses

Recyclers often prioritize safety — which is essential — by discharging cells, shredding under inert atmosphere, and adding thermal safeguards. Those measures are necessary but add operational complexity and sometimes waste pathways (e.g., inert gas use, cooling and scrubber water) where trace metals can be dispersed. The balance between safety and recovery efficiency is delicate: over-robust safety measures without proper material capture planning can increase the fraction of material lost to secondary waste streams.

Economic decisions that shape recovery fractions

Recovering the last few percentage points of a metal often costs disproportionately more than recovering the first bulk fraction. If metal prices are low or capital is tight, plants may choose to leave complex lithium recovery steps unimplemented and focus on the high-value cobalt/nickel streams. That economic triage is a major reason some metals remain under-recovered: it’s cheaper to accept some loss than to invest in additional processing.

Design and format choices that change loss risk

The physical format of cells affects loss. For example, pouch cells can swell and leak, making shredding riskier and increasing the chance of electrolyte escape. Cylindrical cells are robust and standard, which aids automation and reduces accidental losses. Prismatic cells glued strongly into modules increase disassembly time and damage risk. Design-for-recycling can reduce loss risk by enabling cleaner delamination and less destructive pretreatment.

Practical levers to reduce losses — what works right now

Several practical steps reduce material losses. Upstream sorting (digital passports, simple sensors) improves feed quality. Mechanical delamination techniques that remove electrode layers intact enable higher direct-recycling yields. Integrating pyro and hydro steps carefully — capturing lithium from slag with downstream hydrometallurgy — reduces lithium loss. Closed-loop water and reagent systems minimize dissolved-metal emissions. Dust and fume capture with fine-particle recovery lowers airborne losses. Finally, policy and procurement that pay a premium for battery-grade recycled materials tip the business case to invest in additional recovery steps.

Longer-term tech fixes: direct recycling and improved anode recovery

Direct recycling that reconditions cathode powders promises to keep more material in battery-grade form if you can delaminate and relithiate without contamination. Likewise, better processes to purify and reconstitute graphite to battery-grade anode material would close a major loop. Both are active research areas and would significantly lower the current “at-risk” profile for lithium and graphite if they scale economically.

Policy and systems levers that incentivize full recovery

Regulations that mandate minimum recovery rates or require reporting of material flows can force investment in lithium and graphite recovery. Extended producer responsibility (EPR) schemes that internalize end-of-life costs encourage manufacturers to design for disassembly and to support collection systems that provide cleaner feed. Public procurement and recycled-content mandates for battery materials create demand for higher-purity recovered outputs, making investments in marginal recovery steps pay off.

Conclusion

Some metals — notably lithium and graphite — are currently most at risk of being lost in many real-world recycling operations, especially when pyrometallurgical-only flows or crude shredding are used. Other elements like nickel and cobalt are usually recovered well in hydrometallurgical systems, but only if feedstock is reasonably sorted and pretreatment is done properly. The path to higher circularity is clear: better upstream sorting and collection, investment in lithium- and graphite-focused recovery technologies, design-for-recycling by manufacturers, and policy that aligns incentives for full-material capture. If industry and policymakers focus on those levers, the lost fractions today can become the recovered materials of tomorrow.

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Peter

Peter Charles is a journalist and writer who covers battery-material recycling, urban mining, and the growing use of microreactors in industry. With 10 years of experience in industrial reporting, he explains new technologies and industry changes in clear, simple terms. He holds both a BSc and an MSc in Electrical Engineering, which gives him the technical knowledge to report accurately and insightfully on these topics.