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The current focus for the engineering industry is ensuring a sustainable future for the planet. It is widely believed that this future means updating current technologies, such as automobiles, to run on purely electrical power. The largest hurdle for this future is the storage of this electricity in order to be used on the go. The optimization of the conventional rechargeable battery is now an imperative area of research.
Currently, most of the rechargeable batteries use lithium-ion which were first developed in the early 1990s. These batteries revolutionized consumer electronics and can be found in everything from mobile phones to laptops. Leaps in the field have meant that the lithium battery gets 5-10% more efficient every year which has allowed for the emergence of a viable electric car.
However, with the structural optimization of this type of battery reaching its limit, and the demand for energy storage growing, more research into battery technology is needed in order to satisfy consumer needs. However, battery research is extremely difficult. To appreciate just how much, it is important to understand the current design or conventional lithium batteries.
The traditional lithium battery is constructed of one cell, consisting of two electrodes sandwiching an electrolyte. When the electrodes are connected, an electrochemical process starts. Lithium ions and electrons separate in the anode, the positive lithium ions move to the cathode and combine with the lithium ions again. This process is reversed for rechargeable batteries. The reason why lithium is the best material for this process is that it is very reactive and is the lightest metal. This means the batteries can be lighter and have the least amount of chemical complications.
To improve upon this battery structure, researchers are experimenting with different materials for the electrodes and electrolyte in order to develop the largest possible electrical potential difference, thereby making a better battery.
Electrolytes are usually made from liquid due to the fact that it is much easier for electrons to flow freely in a liquid rather than a solid material. One of Europe’s most famous nanotechnology research and development centers, IMEC have been exploring a new material based on a nanoporous oxide mixed with other ionic compounds as a potential electrolyte material. The pores give the material total surface are of 500m2/mL. This incredible development means that the nanoengineered solid is “comparable to an Olympic swimming pool folded into a shot glass” according to IMEC’s head of battery research Philippe Vereecken. This property means that the material has a conductivity which is equal to that of conventional liquid electrolytes.
Electrodes, on the other hand, are usually built from compressed powders. Vereecken’s team hope that a solid electrolyte could also be made from powder, ensuring maximum contact and therefore promises to “store more energy than today’s technology allows”.
There are many areas of research. One of the theories is to combine solid electrolytes with larger electrodes made from finer particles in order to create batteries witch larger energy densities. Another idea is to replace the current graphite anode with silicon, which is known to be able to hold approximately 10 times the amount of lithium ions per gram of electrode. Unfortunate, silicon anodes will expand to three times its size as it fills with lithium ions, therefore causing some sizing concerns.
Battery research is complicated and time-exhausting. A global effort is needed in order to overcome the current hurdles in the industry and ensure a cleaner, electrical future.
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