Background

With a rapid rise in the number of sold electric cars worldwide, the issue of reusing their critical components is becoming increasingly important. One of the key issues is the recycling of lithium ion batteries. The need in battery recycling is driven by multiple factors, including economic, environmental and ethical. However, the complexity of the battery structure and the costs of the labour associated with manual disassembly prompts the search for more automated, more energy and cost efficient methods to recycle the battery components and recover critical metals.

Technology Overview

A multidisciplinary team from the University of Birmingham has developed a number of solutions to the battery recycling challenge, applicable to various recycling lines and approaches. One of them is a new technology to selectively remove spinel (or other Mn rich phase) from the mixed phase cathode materials. It allows the recovered material to regenerate spinel directly, without the addition of extra metals. The cathode materials obtained from regenerated spinel demonstrate good cyclability. Moreover, the same spinel can be used to make new cathode materials (for example, Mn-rich O-redox cathodes).

A significant advantage of this method is that it can gently treat separated cathodes and, potentially, black mass, while using low-cost, non-toxic chemicals and water. The non-spinel phases can be subsequently regenerated via other, already well-known routes, significantly decreasing the amount of recycling waste.

The invention is based on chemical extraction (leaching process) using non-hazardous organic acids and reducing agents that do not require refrigerated storage – i.e. no need in H2O2 (the most common reducing agent). The whole process occurs in water solution ‑ is safe, green and waste‑disposal friendly.

The process has been demonstrated on the separated cathodes – it required only 10 min for treatment of end-of-life Gen 1 Nissan Leaf battery (ca. 300 kg). It can also be adjusted to address the failed batteries and the end-of-life batteries discriminately, to optimise the process and reduce steps required for a full battery treatment.

Benefits

• Highly selective ‑ only the Mn‑rich phase (spinel) phase is extracted while the rest of the cathode can be treated with known methods
• Versatile ‑ the method can treat a mixture of different generation cathodes without a need for separating them
• Rapid ‑ the extraction of the cathode materials occurs in minutes (for Nissan Leaf Gen 1 battery)
• Efficient ‑ the extracted solution is used to obtain Mn‑rich directly without additional metals.
• Can be used in combination with other recovery processes for subsequent recovery of other phases (e.g. hydrothermal hydroxide process for NMC cathodes)
• Recovered phases can be upcycled to the next generation cathode materials
• Uses inexpensive non-toxic chemicals (water solutions of non-hazardous substances)
• The amount of recovered material can be determined by simple weighing, with exceptional purity (ICP or other similarly complex methods are not required)
• Very good cycling of the recovered materials
• Flexible and adjustable process.

Applications

Electric car battery recycling; lithium battery recycling.

Opportunity

Collaboration; joint research; licensing.