Recycling Lithium-Ion Batteries to Make New Cathode Materials

This patent describes a method for recycling used lithium-ion batteries by dissolving their cathode materials, adjusting the metal ratios in a liquid, and then pulling out a custom mix of materials for new batteries without needing extreme heat.

What it covers

This method recycles lithium-ion batteries by first crushing the old battery material and mixing it with an acidic liquid, like sulfuric acid, and hydrogen peroxide to create a "leach solution" (Claim 1). This process separates the useful cathode materials, such as cobalt, nickel, manganese, and aluminum, into dissolved salts, leaving behind undissolved parts. The patent then details determining the exact mix, or "molar ratio," of these dissolved metals. Based on what's needed for a new battery, additional metal salts (like nickel, cobalt, manganese, or aluminum sulfates or hydroxides) are added to the solution to achieve a specific desired ratio (Claim 1). A chelating agent, such as 5-sulfosalicylic acid, is added with aluminum sulfate (Claim 11). Finally, the liquid's pH is raised to at least 10, causing the desired metals to "coprecipitate" (fall out of solution together) as a combined hydroxide or carbonate, forming a "charge material precursor" (Claim 1). This precursor can then be heated with lithium carbonate to become active cathode material for new batteries.

What it doesn't cover

• —Does not cover recycling methods that separate useful elements into individual pure metals before recombining them, as it emphasizes keeping them commingled.
• —Does not cover processes that do not involve adjusting the molar ratio of the dissolved cathode material salts to a predetermined target.
• —Does not cover methods that precipitate the desired cathode materials at a pH lower than 10.
• —Does not cover recycling processes that omit the use of hydrogen peroxide during the initial leaching step.
• —Does not cover methods that do not include adding a chelating agent when adjusting the solution with aluminum sulfate.

The clever bit

The cleverness lies in avoiding the energy-intensive step of separating each metal individually. Instead, the useful metals remain mixed in the solution, their ratios are adjusted, and then they are made to precipitate together directly into a combined cathode precursor, saving significant energy and simplifying the process.

Why it matters

Lithium-ion batteries power everything from phones to electric cars, and their demand is growing rapidly. Recycling these batteries is crucial to reduce reliance on mining new raw materials, conserve valuable resources like cobalt and nickel, and minimize environmental waste. This patent offers a more energy-efficient way to recover these critical materials by avoiding the high heat typically needed to separate individual elements, making the recycling process more sustainable and cost-effective.

Real-world examples

• 1.Recycling facilities for electric vehicle batteries
• 2.Recycling plants for consumer electronics batteries
• 3.Production of new cathode materials for battery manufacturers
• 4.Closed-loop supply chains for battery components