In our February 2022 issue of Battery Materials Review we presented an in-depth analysis of the LFP supply chain. As we noted in that article, most industry participants assume that, since LFP is derived primarily from easy to find materials, then there will be no issues with the supply chain, despite the huge planned increase in LFP cell production capacity.

We beg to differ.

Our analysis identified a number of major pinch points in the supply chain and we’d like to discuss one issue in more detail here.

Phosphoric acid (p-acid) is a key intermediate material in the production of lithium iron phosphate for the battery material supply chain. Currently there are two primary methods used in industry for the production of p-acid; the Turner (or Dry) process and the Wet process.

Turner process dominates in China

The Turner or Dry process of manufacturing p-acid is what we call a pyrogenic process, which involves feeding phosphate ore into an electric arc furnace and heating it with coke and silica. This is carbon- and power-intensive and produces yellow phosphorus, as well as a waste slag material. The yellow phosphorus is then heated again in air to form P2O5 (plus carbon monoxide and large amounts of dust), which is then cooled in water to produce phosphoric acid.

This is a dirty process which requires large amounts of power and generates substantial amounts of waste material. One has to assume that, with autos companies increasingly focusing on ESG, this process will NOT be acceptable in the supply chains of most Western World OEMs going forward.

Wet process more environmentally friendly, but…

The so-called Wet process to manufacture p-acid is much more widely used in the West. And, to be fair, it is starting to be used in China as well.

In this process, phosphate ore is combined with sulphuric acid. This is an exothermic reaction which produces heat (which can then be used for other things) and a by-product, gypsum. Gypsum is a building material and has a number of industrial uses. The process produces a dilute form of p-acid, which must then be concentrated to produce a more pure form.

On the surface, this looks all well and good, but there are some major draw backs to the wet process:

1) It requires higher grade phosphate ore than the dry process; and
2) Only c.10% of the p-acid produced can economically be used in LFP manufacture (the rest is viable for other uses of p-acid, such as fertiliser manufacture).

LFP expansion will pressure supply chain

The supply chain for LFP is fine as it is currently but the magnitude of the expansion in capacity for LFP batteries, coupled with the increasing ESG focus of battery users, is likely to put extreme pressure on different aspects of the supply chain going forward.

We see bottlenecks emerging in at least four different raw and intermediate materials in the LFP supply chain. Phosphoric acid is just one of the areas where we have identified a potential major issue.

This blog is based on the full length analysis included in the February 2022 issue of Battery Materials Review.