Lithium Application

By November 13, 2018Lithium

Currently, lithium’s demand is rooted in the following applications (in no particular order):

Lubricant Grease – An estimated 2.38 billion pound market, in which lithium-based greases make up 75%. Lithium-based greases generally have good stability, high temperature characteristics and water-resistance properties.

Glass – Lithium typically sourced from the mineral spodumene reduces the viscosity and thermal expansion of glass and, therefore, leads to increased melting efficiencies and/or larger effective furnace capacities. The end result is a substantial energy savings for the glass manufacturers.

Ceramics – Lithium is used in the ceramics industry to produce glazes. The glazes improve a ceramic piece’s shock absorption and stain resistance, protecting the piece against damage. Lithium carbonate is typically used for this application.

Health Products – Lithium, in small amounts (around 0.170 mg/L), is prescribed to those with bipolar disorders or individuals with depression who don’t respond to anti-depressants.

Batteries – Batteries are possibly the best known lithium application of all. It’s where the future lays for lithium demand. This will be explained further in the next section.

Batteries

Why is lithium used in batteries? Simply, with current technology, lithium provides the best combination of energy density (weight to power ratio) and price.

Batteries have essentially three main components: cathode, anode and electrolyte. When the cathode and anode are connected via a wire, for example, electrons flow from the anode through the wire to the cathode, creating an electrical current.

Currently, there are an estimated 80 different lithium-ion battery chemistries in production, with these varying chemistries all exhibiting different characteristics, such as capacity and voltage. Lithium is typically found in the cathode of the battery, commonly in the form of lithium cobalt oxide, while the electrolyte is commonly in the form of a lithium salt, such as LiPF6, LiBF4 or LiCLO4. The anode material is commonly carbon-based, with graphite being the most popular.

Overall, a lithium ion battery’s output is around 3.6 volts, which is more than twice as much as its alkaline cousin.

What does the current lithium demand by application look like?

Source: Deutsche Bank Markets Research – Lithium 101 – pg.23

Projected demand for 2025 is much different, not only in overall demand tonnage, but the percentages each application encompasses. The future is expected to be bright for batteries in the non-traditional markets; electric cars, e-bikes, and energy storage.

Source: Deutsche Bank Markets Research – Lithium 101 – pg.23

What is Lithium Ion Battery and What is Inside a Lithium-ion Battery Pack?

From a tiny Li-ion battery that powers your smartwatch to the massive Li-ion batteries that power an electric car, one thing remains common: These batteries are always made up of four different components; namely, anode, cathode, electrolyte, and separator. In the case of a Li-ion battery, the metal lithium forms the cathode and it is the chemical reactions of lithium upon contact with the electrolyte that make these batteries characteristic. However, it would be important to note here that lithium in itself is a highly unstable element when used inside a battery’s apparatus. Hence, a combination of lithium and oxygen together, called lithium oxide is used as the cathode for practical purposes. That is because lithium oxide is a much more stable compound as opposed to elemental lithium.

The cathode plays a huge role in determining the characteristic of the battery. Both, the battery’s capacity and voltage are determined by the type of active material coated on the cathode. The active material, in this case, contains lithium ions. The higher the number of the ions, the bigger the capacity; and the higher the difference in potential between cathode and anode, higher the voltage.

A Lithium Ion Battery uses a separator to separate the cathode from the anode because otherwise, not only will there be no current, but the safety of the entire system would be compromised.

Applications of Lithium-Ion Batteries

As established above, Li-ion batteries are available in all shapes and sizes. And that renders them to be the perfect option for power needs irrespective of the size of the system. Along with that, lithium-ion batteries offer power solutions across the spectrum- from energy storage solutions to portable energy solutions. Some of the most common applications of lithium-ion batteries are:

  • Power backups/UPS
  • Mobile, Laptops, and other commonly used consumer electronic goods
  • Electric mobility
  • Energy Storage Systems

As there are varied uses of a Lithium Ion Battery, it comes in different types of packaging. However, there are some general advantages of using a Li-ion battery over other traditional batteries

Advantages of Lithium-Ion Batteries

High Energy Density: One of the biggest advantages of a lithium-ion battery is its high energy density. To put it straight, lithium-ion batteries can last way longer between charges all the while maintaining a high current output. That makes it the perfect battery for most modern needs. As we spend more and more time on our mobile phones, lithium-ion batteries can make sure that we are on the go always and spend minimal time attached to a charging cord.

Low Self Discharge: Not only whilst being used, but lithium-ion batteries have a clear advantage when not being used as well. When kept idle, the rate of self-discharge, a common phenomenon in batteries, is extremely low. In fact, in most cases, it is as good as being negligent.

Low to Minimum Maintenance: Lithium-ion batteries are popular for their low maintenance batteries too. Most other cells like Nickel Cadmium batteries have a huge cost of ownership and maintenance.

Options: One of the biggest advantages of lithium ion batteries is the fact that they come in all shapes and sizes- presenting users with a large number of options to choose from according to their needs.

It must, however, be noted that it is not all hunky dory in the land of lithium. A Lithium Ion Battery comes with its own flaws too.

  • Present Day Lithium Ion Batteries

The present day market for lithium ion batteries is far more complicated than the original small electronic devices for the 3C market mentioned above. Many additional markets have been opened for small devices such as toys, lighting (LCD and fluorescent lights), e-cigarettes and vaporizers, medical devices, and many others. The discovery that lithium ion battery packs using 18650, 26700 and 26650 sizes can be designed to operate at much higher power than originally suspected has opened markets for portable electric tools, garden tools, e-bikes and many other products. While high energy 18650 cells now have as much as 3.4 Ah, the high power cells have sacrificed some capacity to obtain 20A or higher continuous discharge capability in the 18650 cell size. While some cells claim as high as 2.5 Ah capacity, it is difficult to sustain such a high capacity during cycling. Modeling studies by Reimers and Spotnitz and coworkers show clearly the important effect of multiple tabs and tab placement. Other important design variables are the electrode thickness, the carbon content of the positive electrode, the porosities of the electrodes and the type of carbon used in the negative electrode.

In addition, the development of ceramic coatings to the separator or the positive electrode has had a beneficial effect on preventing internal short circuiting during cycling due to adventitious presence of metal particles on the surface of electrodes. These particles are small and generally airborne and frequently result from mechanical slitting of the electrodes. The separator is only of the order of 12 to 25 μm thick so the concept that very small conductive particles can penetrate the separator and cause a short has been acknowledged as a major failure mechanism of lithium ion batteries. Such separator coatings may be on one or both sides of the polyolefin separator and may be as thin as 2 μm thick. Additional advantages of coating the separator are a much reduced shrinkage of the separator at shutdown temperatures (shutdown of current due to separator melting may not be successful if the separator shrinks to the extent that direct contact between anode and cathode is permitted), better cycling in the case that a weak short circuit degrades capacity during cycling without causing a safety incident, and improved electrolyte wetting because of the easily wet inorganic oxide ceramic phase. Even more complex coatings are becoming common as for example, the Sumitomo separator used by Panasonic and Tesla Motors involves a coating with ceramic particles as well as an aromatic polyamide (aramid polymer) to increase the penetration strength of the coating.

While it is difficult to get confirmation from the battery industry, it seems clear that silicon in small amounts is now added to the graphite based negative electrode. The extremely high specific capacity of lithium silicon alloy anodes (over 3000 mAh/g compared to the maximum of 372 mAh/g for graphite) means that even a small amount of silicon incorporated into graphite particles has a marked effect on the specific capacity of the negative electrode. There are many ways already investigated to include a small amount of silicon micro or nano particles onto the surface of graphite particles and each graphite supplier uses their own proprietary process. For example, 400 to 500 mAh/g materials are commonly available now and are no doubt used in the premium lithium ion batteries providing over 3 Ah capacity in 18650 cells. These cells have high cycle life as well as high capacity and are only slightly more expensive than conventional graphite cells.

Present cathode materials in common use include the original LiCoO2 (abbreviated as LCO) and LiMn2O4 (abbreviated as LMO). An excellent and still developing material is LiNixMnyCo1-x-yO2 (generally called NMC and of the same R3-m structure in the original Goodenough patent5 except for some ordering in the transition metal layer). The subscripts are usually called by their atomic ratios as 532, 442 or 811 (except for the initially investigated x = y = 1/3 which is called 333 or111). The most commonly used materials are 111 and 532. In addition, a highly competitive material is LiNi0.80Co0.15Al0.05 (NCA), also a layered R3-m structure. A more recent material developed competitively by several groups is LiFePO4 (LFP) with a 1D tunnel structure. Each of these materials has certain advantages and disadvantages and has been applied to different applications.

Properties of various cathode materials used in commercial lithium ion batteries at the present time and the advantages, disadvantages and applications in full cells. LCO is LiCoO2, LMO is LiMn2O4, NCA is LiNi0.8Co0.15O2, NMC is LiNIxMnyCo1-x-yO2, and LFP is LiFePO4.

A snapshot of the battery industry in early 2015 may be obtained from the work of Pillot, now available on the internet. Pillot has a reputation for providing accurate data on present production as well as a conservative approach to extrapolated values for future production. Reference to Pillot shows that the battery use of LCO is still the largest at 45 kilotons (KT) of material, but definitely leveling off. The use of NMC is next at 35 KT and growing, LMO is next at 18 KT and growing somewhat, LFP at 10 KT seems to be leveling off, and NCA at about 9 KT is growing strongly. The expense and supply concerns have limited the upside potential of LCO and there continue to be safety incidents, especially with lower volume cell producers. Two of the newer applications, electronic cigarettes and so-called hoverboards (2 wheeled self-balancing boards) have had numerous safety incidents reported in which the lithium ion batteries have sparked and flamed causing injuries and property damage. A U. S. Fire Administration document reported in 2014 on at least 25 fires related to lithium ion batteries in electronic cigarettes, and many more have been reported in various media since. CNet reported that as a result of over 60 fires, over 501,000 hoverboards have been recalled by the US Consumer Product Safety Commission. It is certainly in the interest of the battery industry to strongly react to prevent such occurrences as rapidly as possible. Part of the investigation of such incidents should be to identify the components of cells, particularly the cathode, the separator and the electrolyte. The rapid rise of NMC is partly due to the flexibility of the material for both high energy and high power applications. Thus, many power tool batteries that originally had LMO as the cathode material, now have NMC. Also, consumer electronics applications frequently use NMC because of easier manufacturing processes than NCA and the various cell geometries possible with this material (cylindrical, pouch, and rectangular cells). The disadvantage listed is the patent issue. This is a complicated legal issue, but two patent holders, BASF-Argonne National Laboratory and 3M have competing patents in the US related to similar materials with excess lithium and manganese, which have introduced difficulties in batteries sold in the US. NCA is used by a few major producers such as SAFT and Panasonic to make high energy and in some cases, high power cells. These are generally premium cells and have the highest cost as a result. LFP has lower energy density because of its lower voltage and generally lower tap density, but, because of its good power and good thermal stability, has been used in more rugged applications such as e-bikes to good effect. The reader is referred to Reference for structural details and other property measurements of these materials.

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