What chemical analysis techniques are essential for lithium-ion battery manufacturing?

By Emily Newton, revolutionized.com

Lithium-ion battery analysis is vital for ensuring manufacturers produce safe, high-quality batteries. Several essential techniques can reveal a wealth of information about each component of a li-ion battery, and companies can use them to carefully analyse their entire battery from cathode to anode.

Current Collectors

The cathode and anode current collectors are typically the outermost components of a lithium-ion battery. These parts are connected to the cathode and anode and are usually made of foil. Manufacturers should focus on verifying high chemical purity when testing them.

For example, a battery might have an aluminium foil cathode current collector and a copper foil anode current collector. Each should be greater than or equal to 99.9% pure. Manufacturers can use glow discharge mass spectroscopy (GDMS) to test the purity of each current collector.

GDMS involves sputtering atoms from a solid sample and ionising them in a plasma. The ionised atoms are then deposited in a mass spectrometer. GDMS is a great chemical analysis technique for li-ion battery manufacturers because it requires little sample preparation and returns results in under two hours.

Li-Ion Cathode

The cathode is at the positive end of the battery. Lithium-ion battery analysis for this component should focus on verifying the presence of positive and conductive materials and identifying chemical impurities. There are several tests manufacturers can use to analyse these traits.

For example, manufacturers can detect chemical impurities using inductively coupled plasma mass spectroscopy (ICP-MS). This is a powerful chemical analysis technique for detecting elements, particularly metals. ICP-MS can find contaminants down to the nanogram per litre level.

It is worth noting that ICP-MS is designed for liquid samples, not solids. Manufacturers can also use GDMS testing to further analyse the presence of impurities. GDMS works with solid samples, making it a good complement to ICP-MS testing.

Inductively coupled plasma optical emission spectroscopy (ICP-OES) is also helpful for cathode analysis. Manufacturers can use ICP-OES and thermal checks to test the presence and performance of the cathode’s positive and conductive materials. Thermal tests can also confirm the performance of binding agents in the cathode.

Ceramic Membrane

The ceramic membrane or separator is usually located between the cathode and the electrolytes chamber of the battery. Lithium-ion battery analysis for the membrane should prioritise confirming high chemical purity.

Aluminium oxide powder, also known as alumina, is the most common material used for ceramic membranes. This chalk-white compound should demonstrate high chemical resistance, compression tolerance, dielectric strength and temperature resistance.

Manufacturers can test ceramic membrane purity and quality using various techniques, including GDMS, DSC and TGA. GDMS testing is the most common analysis method for confirming purity. The membrane’s alumina powder should be at least 99.995% pure, so careful GDMS testing is crucial.

DSC and TGA are effective methods for thermal analysis. Differential scanning calorimetry (DSC) can provide valuable information about the membrane’s degradation properties, such as melting profile and electrolyte decomposition. Understanding them gives manufacturers important insights into their batteries’ safety and longevity.

Additionally, thermogravimetric analysis (TGA) is helpful for studying the thermal stability of the membrane material. This is another important safety-related factor since low thermal stability can cause unwanted chemical reactions due to over- or undercharging. Thermal stability testing is particularly crucial for EV batteries, which can be subject to drastic temperature fluctuations, such as during quick charging.

Li-Ion Electrolytes

The electrolyte is one of the most important components of any lithium-ion battery. It serves the crucial purpose of moving ions between the cathode and anode, allowing the battery to function.

Verifying that this particular component is operating properly is vital for safety and success. Analysing chemical purity in the electrolyte is especially crucial due to the high risk of hazards caused by impurities. Reactions due to impure chemicals have caused chemical plant explosions and pose serious fire hazards.

Manufacturers can conduct various lithium-ion battery analysis procedures to test the electrolytes. Testing should prioritise confirming metal purity and analysing solvent and electrolyte composition. ICP-MS, ICP-OES, GDMS and GC-MS are the most appropriate chemical analysis techniques for accomplishing this.

Like cathode testing, ICP-MS and GDMS are good for checking metal purity. Which technique is best for a certain battery depends on the type of electrolyte. ICP-MS is ideal for liquid or polymer electrolytes, while GDMS is better for ceramic electrolytes. Manufacturers can use ICP-OES with these techniques to test electrolytes’ chemical composition.

Li-Ion Anode

The last component of a li-ion battery is the anode, the negative end of the cell. Testing should confirm graphite and metal purity and analyse silicon and carbon composition. The best lithium-ion battery analysis techniques for this stage include ICP-OES, ICP-MS, GDMS, DSC, TGA and IGA.

Manufacturers can use GDMS to test the anode’s graphite purity. An ultra-high 99.995% is typically required, so a careful GDMS process is essential. ICP-MS is ideal for identifying metal impurities in the silicon-carbon composites and the binding agent.

An instrumental gas analysis (IGA) is also helpful for anode testing. IGA measures the presence of gas-forming elements, including carbon, hydrogen, oxygen, sulphur and nitrogen. It can precisely verify the amount of carbon in silicon-carbon composites and detect any oxygen impurities.

Thermal analysis using DSC or TGA is also recommended. Much like membrane testing, both chemical analysis techniques can reveal important thermal properties in a battery. They’re vital for confirming longevity and thermal stability.

Why Lithium-Ion Battery Analysis Is Important

Conducting all these tests may sound time-consuming, but it serves a crucial purpose in battery manufacturing. Lithium-ion battery analysis ensures safety, performance, longevity and high product quality. These traits are especially important in large batteries for electric vehicles and industrial applications.

Additionally, lithium-ion battery analysis can help manufacturers improve their products. Strengthening researchers’ understanding of a battery’s components and how they interact can reveal opportunities for improvement and innovation. Chemical analysis is also vital for making these updates safely.

For instance, many battery manufacturers are transitioning to lithium iron phosphate (LFP) batteries to reduce their reliance on unsustainable cobalt mining practices. Substituting cobalt with LFP can improve battery quality but requires careful chemical analysis testing to ensure success and safety.

Conducting a Successful Lithium-Ion Battery Analysis

Lithium-ion battery analysis is essential for manufacturing safe, high-quality batteries. Effective analysis techniques are crucial amidst the rising popularity of electric vehicles and industrial equipment. Large, high-density batteries require comprehensive chemical analysis to ensure they are safe and effective for consumers and businesses.