Approaches to Improving Manganese Circularity in Lithium Ion Batteries
Dr Michelle K. Lynch CChem FRSC, CEO, Enabled Future Limited
Snapshots of Battery Chemistries
The chemical formulations of cathode materials for lithium ion batteries (LIB) have changed over the last decade to meet the evolving needs of different applications. For instance, in electric vehicles (EVs) driving range, power performance, low temperature operation, battery life requirements and many other parameters have dictated the need for LIB technology improvements. One of the major trends in recent years was to reduce the amount of cobalt (Co) in LIB and to increase the amount of nickel (Ni). This had a two-fold benefit – reducing the demand for Co to a level where responsible supply could be managed and increasing the energy density of the battery by incorporating higher levels of Ni. However, as discussed in this month’s EnabledCircular feature, Ni prices have seen volatility and all time high prices over the last two years.
As a result of the market dynamics of Co and Ni, there is a desire to use more earth abundant metals in LIB and other rechargeable battery types. One way this can be achieved is by using higher levels of manganese (Mn) in place of the Ni. There are two main types of battery chemistry with predominantly Ni and Mn – the spinel-type lithium nickel manganese oxide (LNMO) and layered-oxide types (NMx) and high Mn NCM. Doping of lithium iron phosphate (LFP) to produce LMFP is another source of Mn demand.
The percentage by weight of Ni, Co and Mn in different battery chemistries are summarised in Figure 1 and Table 1. NB in this analysis, NCA and LFP are not included as they do not contain Mn. The trajectory of cathode chemistry development as discussed above moved from formulations with relatively high levels of cobalt e.g. NCM111 to those with higher nickel e.g. NCM811 and NCM955. To those unfamiliar with these codes, the numbering system corresponds to the relative amount of Ni, Co and Mn on a molar basis. The percentages in the chart and table refer to weight content of the pure cathode material powder prior to mixing with any coatings, binders or additives. The highest Ni content is seen in NCM955 (54 wt%) which contains only 3% Mn.
Forecasted Manganese Demand
With most EV batteries coming onto the market expected to be high-nickel NCMs, it could be assumed that Mn would not have the level of supply criticality as do Ni and Co. However, this is not predicted to be the case. A recent analysis from Benchmark Mineral Intelligence indicates that for the NetZero scenario, Mn demand is set to rise by almost 600% between 2025 and 2040 with over 1.2 million tons of Mn required per annum by the end of that forecast period. Even more interesting, is that the largest portion of 2040 demand is expected to be for non-NCM Mn rich LIB chemistries. (Fleming, 2023) (See Figure 2 below). This has implications, not just for sourcing sufficient battery grade Mn to produce the batteries, but also for incorporating recycled content in those battery formulations in the near term and recycling them in the long term.
Sources of Mn Supply
Manganese is supplied from primary mining operations. In total 20 million tons of Mn was mined in 2022 with South Africa being the largest producer (35%), followed by Gabon (22%) and the USA 16.5%. (USGS, 2023) There is no European country with a significant primary manganese mine supply – only Ukraine and Kazakhstan produce and this is from concentrates.
While the amount of Mn mined globally is much higher than that required for LIBs, there is currently insufficient capacity for producing enough high purity Mn (HPM) suitable for battery grade cathode material to meet future demand. Only 1% of the ore produced goes to HPM and most HPM is produced in China. The remainder is for steel ferroalloys (91%) and lower grades of electrolytic manganese and Mn sulphate (8%). (Fleming, 2023) In addition, while Mn is not part of the current draft of EU regulations for recycled content in LIB, the ESG goals of battery and EV OEMs may require it anyway. Therefore, there is a need to find secondary and sustainable sources of Mn for future LIB demand.
Figure 3 shows three different secondary sources of Mn – recycled LIB, other recycled batteries and sustainable mine sources along with their advantages and disadvantages. Considerations for these options are discussed in the proceeding sections of this article.
Manganese from Recycled Batteries
LIB cathodes need to have recycled content in line with the forthcoming EU Battery Passport regulations. (Popp, 2022) Although Mn is not included in these regulations currently, cell makers and EVs also require recycled content in LIBs to meet their ESG goals and this includes the Mn content – especially for Mn rich batteries. Therefore, cathode material producers in Europe are looking to source recycled content for their products. Recycled content is generated at metal refineries across all the key battery metals in the form of metal salts e.g. Ni, Co, Mn sulphates from so-called “black mass” generated from shredded waste batteries. These salts can also be recovered from treating other types of waste Mn e.g. non-LIB that contain Mn as well as scrap from metallurgical operations, catalysts and other industrial materials. The refiners then supply the cathode material producers with metal salts and solutions that have a % of recycled content mixed with virgin content.
One issue with this system is that the metal salts are generated from the output of central hydrometallurgical processing of both mixed waste streams and primary concentrates. Some cell OEMs would like a closed loop supply – whereby only their battery waste is put into the hydromet unit. However, this could only work for the largest companies, so that refineries could justify a separate line just for that OEM’s materials. This isn’t possible yet as there is not enough hydromet capacity in Europe and not enough waste batteries. However, this will change over time as that capacity comes online and waste battery levels rise. One challenge is that refining projects are only bankable if they have green electricity sources – so refiners are competing for “green-electrons”. Many new wind farms in Scandinavia are attracting battery metal refining capacity for this reason.
A second issue is the need to develop specifications for material provided from recyclers/refiners. For well-established battery chemistries such as NCM622 and NCM811, there are already well understood specifications. It should be noted that, according to leading industry contacts, the Mn coming back from recycled materials is not sufficient to be used in high-nickel NCM batteries – and it is not clear how those materials will be supplied. However recycled Mn may be good enough for LNMO. Currently for LNMO there is no long-term data on the battery performance in the end-use application and as yet, not a clear understanding therefore of the exact cathode specifications.
LNMO cathode material producers such as Topsoe in Denmark are working from the existing NCM811 specifications and learning how they should be tailored for LNMO through extensive R&D work on cathode materials containing recycled content.
Some impurities cause more trouble than others for LNMO. For instance, Co isn’t as bad as Fe – it doesn’t reduce performance, it simply doesn’t contribute to it. Whereas for Fe, which can cause self-discharge and shelf-life issues in cells, more specification development is required and testing in end-use applications. Other problem contaminants include Zn, Ca, Mg, P and F.
The pragmatic approach for producing recycled cathode materials is to start with the cheapest recycled salts available in the largest quantities. These are evaluated first and after that smaller and/or more expensive feeds are considered. The ideal is to have a constant supply of material within a range of specifications.
Recycled materials are unlikely to contribute enough to meet the rapidly growing demand for battery grade Mn. The batteries reaching their EoL over the next 10-20 years have only small quantities or no Mn at all i.e., nickel rich NCM, LCO and LFP. A second issue is that it might be difficult to keep recycled materials in Europe as cars have a habit of being sold outside the region – first going to East Europe, then South to Africa for instance. Once this happens it is unlikely that the batteries would be exported back. Attempts to force vehicle batteries to be kept and recycled in Europe are problematic from a sustainability perspective and as discussed in the EnabledMetals news insight, would do little to relieve the pressure on metal demand requirements given the growth in the battery industry.
Manganese from Sustainable Mine Sources
Production of metals from former working mines is another method to generate sustainable battery materials. Euro Manganese, headquartered in Vancouver, Canada is a producer of battery materials with a focus on producing sustainable battery grade manganese chemicals for the EV industry. Its project at Chvaletice, Czech Republic is aimed at large scale reprocessing of Mn from old mine tailings at a decommissioned mine site. The site is reportedly Europe’s largest Mn resource hosted in tailings and is a 25-year project looking to produce 50,000 tons per annum of high purity battery grade products. The output is intended to provide much needed material to plug the current and increasing Mn supply gap. The project involves no hard rock mining is cleaning up a site which is already polluted and produces Mn chemicals at around one-third the carbon footprint of industry incumbents, thereby contributing to the EU’s decarbonisation goals. (Votava, 2022)
In spite of the very positive outlook for Mn in LIB, it is not considered a desirable metal to collect and recycle from LIBs. In fact Mn is currently the last priority for a hydromet after Ni, Co and Li have been recovered. According to industry contacts, it costs as much to recycle Mn as it does Ni and Co combined. When it is recycled, most Mn is not purified back to the grade needed for most batteries i.e., NCM, NCA. The usual output is Mn hydroxide salts when the carbonates would be preferable.
Therefore, there is an industry need to take in a range of Mn-rich precipitates from different industries and process them centrally. According to Euro Manganese, this could be carried out at Chvaletice. Pyrometallurgical units have a Mn-containing slag which is in the form of oxides and silicates. This goes into construction materials currently. With some upgrading, industry contacts believe this could be viable for LNMO/LMFP battery chemistries.
As long the feeds don’t have too much Fe or F, they can be viable for upgrading – companies can also choose to do an extra upgrade themselves then send them for refining – this needs discussion and collaboration between the companies and the refiners. Blending of Mn salts from different recycled materials with purer feeds of Mn e.g., from the mine tailings can be a useful strategy although it needs to be demonstrated.
Patent Landscape for Manganese Recycling
There are relatively few patent publications for recycling manganese-rich batteries compared with NCM/NCA which is not surprising given their early phase of commercialisation. However selected patents and key details are provided for Mn recycling from LIB and other secondary sources in Table 2 below. Most of the patent literature comes from Chinese assignees and amongst those – key universities and institutes as well as the larger recycling companies with hydrometallurgical capacity i.e., GEM and Brunp.
Enabled Future Limited provides ongoing analysis of patents related to the production and recycling of LIB for Mn rich formulations and these are available as a monthly download via subscription.
Key Takeaways
- Cathodes with lower Ni/Co-Free chemistries are growing rapidly e.g., LNMO, NMx, LMFP
- LNMO will be the largest user of Mn in batteries by 2040, even more than high nickel formulations
- The need to meet demand for recycled materials in line with sustainability/ESG goals will require that much more secondary Mn is available
- Recycled Mn is expensive to produce and could be detrimental to battery price competitiveness in the EU – there is a large need to bring down the price.
- Sustainable mine sources can seriously help to bridge the supply gap – and projects such as Euro Manganese Chvaletice, Czech Republic are looking promising.
- Much of the effort needed isn’t necessarily technical – it’s logistical and requires cooperation between different stakeholders.
There is a need to ensure that Mn doesn’t end up in landfill and is actually recycled – ESG practices ought to benefit the industry here.
There are opportunities – however we must be proactive and collaborative in order to realise them.
About The Author
Michelle Lynch is a PhD in Chemicals and Catalysis and is a Chartered Chemist and Fellow of the Royal Society of Chemistry (FRSC). Her 26 years of post-doctoral experience span catalyst R&D, catalyst and precious metals market research, patent analysis and consulting. She is currently the CEO and Owner of Enabled Future Limited (EFL). Prior to setting up EFL, Michelle worked with IHS (S&P Global), Nexant and Johnson Matthey. Michelle is a regular speaker at conferences, editor and contributor to industry magazines including the new Enabled Future magazine. Her publications have also appeared in the IHS Chemical Bulletin, IHS Quarterly, The Catalyst Review, Recycling & Waste World and The Catalyst Group subscriber reports. She lives and runs her consultancy in the West Midlands, UK.
Fleming, A. (2023). Manganese Panel. Benchmark Week (pp. 1-6). Benchmark Mineral Intelligence.
Popp, D. (2022, December 9). Batteries: deal on new EU rules for design, production and waste treatment. Retrieved from Europarl: https://www.europarl.europa.eu/news/en/press-room/20221205IPR60614/batteries-deal-on-new-eu-rules-for-design-production-and-waste-treatment
USGS. (2023). Manganese. Retrieved from USGS: https://pubs.usgs.gov/periodicals/mcs2023/mcs2023-manganese.pdf
Votava, J. (2022, May 17-18). The Chvaletice Manganese Project. Retrieved from re-mine.eu: https://re-mine.eu/wp-content/uploads/2022/06/3_13_EMN-corporate-presentation_2022_05_18-_Conference-Micheleen_Belgium-combined-1.pdf
