Introduction and comparison of battery grade lithium hydroxide

This section describes battery grade lithium hydroxide

Lithium hydroxide is one of the three basic lithium salts in the lithium industry chain, and its main forms are water-free lithium hydroxide and lithium hydroxide

monohydrate. Battery grade lithium hydroxide monohydrate is mainly used for the preparation of cathode materials for lithium ion batteries. It can also be used as

an additive for alkaline battery electrolytes, and can also be used in the manufacture of lithium.

Lithium hydroxide, as the core lithium salt type in the downstream of the lithium industrial chain, is an important raw material in the battery field, especially the

high-nickel ternary cathode material widely used in high-performance batteries, which is an indispensable core lithium source in its production.

Production technology of lithium hydroxide

From the point of view of production technology, lithium hydroxide can be produced one step after lithium sulfate is produced by acidification, or lithium carbonate

can be extracted from salt lake brine first, and then lithium hydroxide can be produced by catalytic method. Therefore, considering the cost of producing lithium

hydroxide from pyroxene, it is more advantageous.

Since the salt lake system has a clear cost advantage in lithium carbonate, while the ore system has a quality advantage and no cost disadvantage in lithium

hydroxide, the new production capacity of lithium compounds in the ore system since 2019 is mainly focused on the battery grade lithium hydroxide production

line.

However, the new production capacity of mica lithium extraction is mainly concentrated in the lithium carbonate production line, whose “quasi-grade” products are

complementary to lithium extraction in salt lakes.

Extract lithium from ore

The main disadvantage of extracting lithium from ore is that, with the exception of a few high-grade resource points (such as the Talison-Greentree lithium mine),

the use of ore to produce lithium carbonate and lithium chloride products is generally in the mid-to-high position of the global cost curve.

From the point of view of cost safety, extracting lithium from ore is more suitable for the production of high-quality products such as battery grade lithium

hydroxide.

Extracting lithium from salt lake water

In terms of current mature technology, lithium extraction from salt lakes is more suitable as a low-cost raw material basis for the production of basic lithium salts

such as lithium carbonate (industrial grade/battery grade) and lithium chloride.

The production of lithium hydroxide requires carbonization on the basis of lithium carbonate products. However, in the future, if the electrolysis, bipolar film and

other processes are mature, it will help the salt lake to achieve a step forward and directly produce high-quality lithium hydroxide products.

Comparison between lithium carbonate and lithium hydroxide

Lithium carbonate and lithium hydroxide are both raw materials for batteries. In the market, the prices of lithium carbonate and lithium hydroxide have basically

been rising and falling. What’s the difference between these two materials?

Comparison with the preparation process

Both can be extracted from Sperdumetene, and the cost is not much different, but if the two are converted to each other, additional costs and equipment are

required, and the cost performance is not high. Different technical routes. The preparation of lithium carbonate is mainly by sulfuric acid method. Lithium sulfate is

obtained by the reaction of sulfuric acid and spudolene, adding sodium carbonate into lithium sulfate solution, and then separating and drying to prepare lithium

carbonate;

Lithium hydroxide is mainly prepared by the alkali process, that is, sodium fluoride and calcium hydroxide. Some people also use the so-called sodium carbonate

pressurization method, which is to prepare a lithium containing solution, then add lime to the solution, and then prepare lithium hydroxide.

In short, spaldorene can be used to prepare lithium carbonate and lithium hydroxide at the same time, but the process route is different, the equipment cannot be

shared, and the cost difference is not large. In addition, the cost of preparing lithium hydroxide from salt lake brine is much higher than lithium carbonate.

The technical difficulty of converting lithium carbonate into lithium hydroxide is relatively small, but the cost and construction period are relatively large. Lithium

hydroxide was prepared from lithium carbonate. It participates in the reaction of calcium hydroxide in lithium carbonate to produce lithium hydroxide. The process

is quite complicated.

However, it is necessary to build a special production line. The production cost per ton is at least RMB6,000, not taking into account depreciation and other factors.

Considering the environmental impact assessment and other factors, the construction period is at least 1-2 years. When the price of lithium carbonate is higher

than the price of lithium hydroxide, the lithium carbonate floating method directly sells lithium carbonate without further production of lithium hydroxide.

The preparation of lithium carbonate from lithium hydroxide is relatively simple, but also requires additional costs. The lithium carbonate solution is obtained by

adding carbon dioxide to the lithium hydroxide solution, which is then separated, precipitated and dried to obtain the lithium carbonate solution. Again, this

process requires the construction of a dedicated production line, which also requires additional costs.

Comparative applicability
Due to the low sintering temperature required for high-nickel ternary batteries, lithium hydroxide has become a necessary lithium salt for the preparation of high-

nickel ternary materials. The preparation of lithium iron phosphate (LFP) by hydrothermal process also requires lithium hydroxide.

nca and ncm811 must use battery-grade lithium hydroxide, while nm622 and ncm523 can use lithium hydroxide or lithium carbonate. In general, the performance

of products produced with lithium hydroxide is more excellent. In particular:

Sintering temperature: The sintering temperature of series 8 and above ternary cathode materials is usually low. If lithium carbonate is used as the lithium source,

it is easy to decompose incomplete due to insufficient sintering temperature, too much free lithium on the surface of the positive electrode, too strong alkalinity,

and increased sensitivity to humidity.

Therefore, high-nickel ternary cathodes usually use lithium hydroxide as a lithium source. The use of lithium hydroxide and lower sintering temperatures can also

reduce the mixing of cations and improve cycle stability. In contrast, the sintering temperature of lithium carbonate usually needs to be above 900 ° C to obtain a

material with stability, and it is difficult to use as a lithium source for high-nickel materials.

Discharge capacity/faucet density: Lithium hydroxide as a lithium source material, the first discharge capacity of up to 172Mah/g, with high faucet density and high

charging and discharging performance.

Consistency: Compared with lithium carbonate, lithium hydroxide has the advantages of good stability and good consistency, and is more suitable for high-end

cathode materials.

Cycle life: The ternary material prepared with lithium hydroxide as the lithium source has more uniform particles, which greatly improves the cycle life of the

ternary material.

In general, battery grade lithium hydroxide of ternary materials is superior to lithium carbonate.