Innovate battery recycling by collaboration

Greater innovation and collaboration across the value chain is required to boost the recycling of lithium-ion batteries (LIBs), according to new research published by Nature.

Academics from eight institutions in the US and UK have investigated the need for more efficient recycling processes to manage the expected surge in end-of-life batteries.

‘Efficient and closed-loop battery recycling strategies are therefore needed, which will require recovering materials from spent LIBs and reintegrating them into new batteries,’ they write.

The research found that methods such as ‘direct recycling’, rather than pyrometallurgical and hydrometallurgical recycling, could cut costs by 40% and lower the environmental impact of secondary pollution.

‘In direct recycling, cathode materials are processed without breaking down their crystal structure. Spent batteries are first manually disassembled and separated into different parts and the cathode materials are subsequently recovered.’

Pilot stage

However, the researchers explain, these approaches are still in experimental or pilot stages and require further optimisation for industrial scale. While existing pretreatment processes such as shredding reduce the size of reactive components and make them inert, they create material mixtures, increasing the complexity of the process.

‘Automated disassembly and cleaner mechanical separation could reduce contamination by shredding and increase recovery efficiency, especially at the industrial scale,’ the report states.

Despite the benefits that recycling in general offers, the researchers argue that several key challenges must be addressed through continued innovation efforts.

Three requirements

First, the development of automated industrial disassembly techniques is essential to increase recovery efficiency and to transition laboratory-scale recycling processes to industrial scales. However, the pursuit of increased energy density and improved safety has led to diverse battery designs from different manufacturers. This diversity complicates the design and automation of disassembly lines.

‘Developing battery designs that make robotic disassembly easier can improve safety during recycling, enhance recycling economics and potentially reduce waste by separating extraneous materials before shredding of cells.’

Second, impurities remain one of the biggest challenges in all recycling processes. Although impurities can be effectively controlled in existing recycling processes, the impurity levels in many recycled materials cannot meet the rigorous specifications required by the battery industry.

Third, other battery types, such as all-solid-state batteries, Li–S batteries, Na-ion batteries and other metal ion batteries, are rapidly being developed. ‘The recycling process designs for these battery chemistries must be integrated into the existing recycling infrastructure (with some adaptations) for maximum savings and efficiency benefits.’

The lead authors of the report, ‘The evolution of lithium-ion battery recycling’, are Xiaotu Ma and Zifei Meng of the Mechanical and Materials Engineering Department at Worcester Polytechnic Institute, in the US.

Their work has been published in the first issue of Nature Reviews Clean Technology.