Friday, 20 March 2015

Battery Life Can Be Improved By Using Glass Coated Sulfur Particles

Even though the battery capacity of the Lithium-ion batteries have been holding us back, these batteries have still managed to take us a long ways in tablets, phones as well as cars over the years. The drawbacks of these batteries have prompted the scientists to look out for alternate methods but nothing has been working out until now. There has been significant amount of curiosity from the people in the lithium-sulfur batteries in the last couple of years and a recent breakthrough experiment conducted by the Bourns College of Engineering at the University of California, Riverside can make these batteries the next big obsession. All it took was a simple glass of the experiment.

Lithium-ion batteries and Lithium-sulfur batteries: 

The traditional Lithium-ion batteries have become a part of different types of models of phones and technologies, mainly as they have considerable amount of energy density as well as comparatively long life. Before these batteries can fail, the user can recharge it for a few hundred times. Apart from this, there is no effect on the memory as it was seen with nickel-metal hydride and older nickel cadmium rechargeable. The lithium-sulfur battery falls short in terms of them being dirty and not because of any memory effects.

Compared to the conventional lithium-ion battery, a new lithium-sulfur battery has ten times more of energy density. Just image a huge Android phone with 30,000mAh of juice unlike the usual 3,000mAh, now this is something to be excited about. The current lithium-sulfur technology has indicated a drop as the lithium and sulfur reaction products starts to clog the works. These products (lithium polysulfides) dissolve in the electrolyte solution and get stuck to the electrodes. This process decreases the overall capacity and there is no solution to reverse this process.

According to the UC Riverside team, this “polysulfide shuttling” process can be prevented by using the nano-scale sulfur beads inside the cathode and coating of the battery with the SiO2. SiO2 is also known as glass. The thickness of the silica sheath is measured in nanometers (Tens). This sheath should not be too thick as it can interfere in the function of the battery. On the other hand, it cannot be too thin as it can lead to the rupturing of the glass layer and further lead to the formation of lithium polysulfides and lead to the structure damage.

Researchers found that coating the glass with the sulfur was able to give substantial improvements in durability however; it was still prone to rupturing. They found that this issue can be addressed by incorporating graphene oxide (mrGO) in the cathode, which added stability apart from making the nanoparticles less prone to rupture. They are however still unable to develop the kind of stability one can find in a commercial lithium-sulfur battery. With batteries becoming non-removable in phones and other devices, it is important that they last for few years. This experiment marks an evolution in the battery.

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