Advantages of lithium-ion batteries

Li-ion batteries

While lithium-ion batteries (LIBs) are all over the world, the truth is we still don’t really know how they work. In particular, as scientists try out more and better new materials for electrodes, each one brings slight variations in function and performance. One of the most promising electrode materials is lithium-iron phosphate, and now researchers have a much better understanding of exactly how it charges and discharges — which should hopefully guide the way to improving those processes.

How does a lithium-ion battery work?

Let’s start off with how the lithium-ion battery works. Batteries store and releases energy by moving electrons from one “end” of the battery to the other. Then we can use the energy from those moving electrons to do work for us, like power a drill. These two battery “ends” are known as electrodes. One is called the anode and the other is called the cathode. Generally, the anode is made from carbon and the cathode from a chemical compound known as a metal oxide (cobalt oxide, for example). The final battery ingredient is known as the electrolyte, and it sits in between the two electrodes. In the case of lithium-ion batteries, the electrolyte is a salt solution that contains lithium ions.

When you place the battery in a device, the positively charged lithium ions are attracted to and move towards the cathode. Once it is bombarded with these ions, the cathode becomes more positively charged than the anode, and this attracts negatively charged electrons.

As the electrons start moving toward the cathode, we force them to go through our device and use the energy of the electrons “flowing” toward the cathode to generate power.

Lithium-ion batteries are great because they are rechargeable. When the battery is connected to a charger, the lithium ions move in the opposite direction as before. As they move from the cathode to the anode, the battery is restored for another use.

Recharging a lithium-ion battery

Of course the fact that the lithium ion battery is rechargeable makes it more desirable and sustainable, but why else are these batteries so widely used?

One reason is that lithium ion batteries can produce a lot more electrical power per unit of weight than other batteries. This means that lithium-ion batteries can store the same amount of power as other batteries, but accomplish this in a lighter and smaller package.

However, one downside to lithium-ion batteries is that they take much longer to charge than other batteries. And of course, there is always room for improvement in efficiency. This is where nanotechnology comes in. In order to improve the efficiency and decrease the charge time of lithium-ion batteries, many companies and researchers are using nanotechnology to make better battery materials.

A lot of research is focused on using nanotechnology to make better electrodes. Using nanomaterials in the electrodes increases their surface area, which provides more places for the lithium ions to make contact. This makes the battery more efficient and also makes it recharge faster.

Advantages of lithium-ion batteries

Generally, lithium ion batteries are more reliable than older technologies such as nickel-cadmium (NiCd, pronounced "nicad") and don't suffer from a problem known as the "memory effect" (where nicad batteries appear to become harder to charge unless they're discharged fully first). Since lithium-ion batteries don't contain cadmium (a toxic, heavy metal), they are also (in theory, at least) better for the environment—although dumping any batteries (full of metals, plastics, and other assorted chemicals) into landfills is never a good thing. Compared to heavy-duty rechargeable batteries (such as the lead-acid ones used to start cars), lithium-ion batteries are relatively light for the amount of energy they store.

Advantages

• High energy density - potential for yet higher capacities.
  
• Does not need prolonged priming when new. One regular charge is all that's needed.
  
• Relatively low self-discharge - self-discharge is less than half that of nickel-based batteries.
  
• Low Maintenance - no periodic discharge is needed; there is no memory.
  
• Specialty cells can provide very high current to applications such as power tools.

Limitations

• Requires protection circuit to maintain voltage and current within safe limits.
  
• Subject to aging, even if not in use - storage in a cool place at 40% charge reduces the aging effect.
  
• Transportation restrictions - shipment of larger quantities may be subject to regulatory control. This restriction does not apply to personal carry-on batteries.
  
• Expensive to manufacture - about 40 percent higher in cost than nickel-cadmium.
  
• Not fully mature - metals and chemicals are changing on a continuing basis.

Read more about Li-ion batteries technologies (watch a video:

http://www.extremetech.com/extreme/184236-how-does-a-lithium-ion-battery-work-and-why-are-lithium-ion-batteries-so-popular

http://electronics.howstuffworks.com/everyday-tech/lithium-ion-battery1.htm

http://auto.howstuffworks.com/fuel-efficiency/vehicles/lithium-ion-battery-car.htm