The electric vehicle (EV) revolution and growing reliance on rechargeable batteries is ushering in a golden age for battery raw materials, including one primary commodity—lithium. The demand for lithium is further driven by the rising need for energy storage, e-bikes, portable electronic devices (including mobile phones), electrification of tools, and other battery-intense applications.
Behind the scenes in this industry is lithium carbonate — an important compound used to make a variety of rechargeable batteries, including lithium-ion batteries (the most common). Specifically, lithium carbonate is used to produce the battery’s cathode and as a starting material and precursor to produce battery electrolytes.
In this blog post we’ll look at why measuring lithium carbonate is important — and also challenging.
We’ll also present a new method for measuring inorganic anions in lithium carbonate.
A New Way to Measure Inorganic Anions in Battery-Grade Lithium Carbonate
Lithium carbonate (Li2CO3) is a significant industrial chemical and one of the most important basic lithium salts. It’s a white salt that works as an inorganic compound. It’s used in many applications, including lithium-ion and lithium polymer batteries, but its main use is as a precursor to lithium compounds used in lithium-ion batteries. While lithium carbonate is not the direct electrolyte in lithium-ion batteries, it is a precursor that plays a role in the production of certain lithium salts used as electrolytes.
Battery-grade lithium carbonate requires specific quality of lithium carbonate that meets stringent purity and quality requirements to be used in the production of lithium-ion batteries. The purity and consistency of the lithium carbonate used in the production of electrolytes directly impact the performance, safety and longevity of the resulting lithium-ion batteries. Manufacturers produce battery-grade lithium carbonate through various purification and refining processes to achieve the desired high purity and low impurity levels.
In the batteries industry, why is studying lithium carbonate important?
Measuring and studying lithium carbonate can help determine lithium salt purity.
One of the key needs for lithium-ion battery manufacturers is high-purity lithium salts — either lithium carbonate or lithium hydroxide monohydrate. While the current standard is 99.5% pure Li salt, battery manufacturers really want at least 99.9% pure, and are interested in getting 99.99%, or even 99.999% pure product. Low impurity rates in lithium salts are critical to battery performance and safety. Impurities, such as sodium, have led to battery failure, overheating and fires.
What about measuring anionic impurities in lithium carbonate? Why is that important?
Measuring inorganic anionic impurities in lithium carbonate samples is important for several reasons, as these impurities can significantly affect the quality and performance of the lithium carbonate and any lithium-ion batteries or other products derived from it. Anionic impurities refer to negatively charged ions that can be present in the lithium carbonate compound. There are four primary reasons why measuring anionic impurities is crucial:
- Battery performance: In lithium-ion batteries, anionic impurities can adversely affect the performance and safety of the battery. These impurities can interfere with the movement of lithium ions between the positive and negative electrodes during charge and discharge cycles, leading to reduced battery capacity, lower energy efficiency and decreased cycle life.
- Electrolyte conductivity: Anionic impurities can alter the conductivity of the electrolyte used in lithium-ion batteries. The electrolyte’s conductivity is essential for efficient ion transport within the battery, and any deviation from the desired levels can impact the battery’s overall performance.
- Stability and safety: High levels of anionic impurities can lead to the formation of unwanted chemical reactions within the lithium-ion battery, affecting its stability and potentially leading to safety issues, such as the risk of short circuits or thermal runaway.
- Battery cycle life: Anionic impurities can promote undesirable side reactions during battery charge and discharge cycles, leading to a reduction in the battery’s cycle life and overall durability.
Are there other reasons to study lithium carbonate?
Yes. With the incorporation of lithium carbonate, lithium-ion batteries have experienced a significant increase in their production and applications. However, more research is needed to further enhance these advantages and applications.
A variety of stakeholders — including battery manufacturers, recyclers and chemical suppliers — have great interest in determining inorganic anions in a saturated lithium carbonate solution and using those values to determine the amounts in the solid. Modern ion chromatography systems can provide many of these measurements including fluoride, chloride, sulfur and phosphate.
Where can I learn more about determining inorganic anions in lithium carbonate?
A recent application note from Thermo Fisher Scientific offers additional insight. It describes a method for the determination of inorganic anions (fluoride, chloride, nitrite, bromide, nitrate, phosphate, and sulfate) in a saturated lithium carbonate solution using a RFIC system with a Dionex IonPac™ AS23 column, carbonate eluent suppressor, and carbonate removal device.
For those in the battery market, the learnings provide new insights into how to determine inorganic anions in saturated lithium carbonate solution. The new method proved to be:
- highly sensitive (MDL 0.02-0.22 mg/L in saturated lithium carbonate solution)
- precise (with RSD range of 1-6%)
- accurate (with a recovery range of 95-107%)
To learn more, download the application note here:
You can find additional information and resources on our Ion Chromatography for Battery Material Testing webpage
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