Overcoming the Major Shortcomings of Lithium-air Batteries Could Simply Require Some New Chemistry
There’s absolutely no doubt about it that lithium-air batteries represent a highly promising technology that can be utilized in some electronic devices that are easily portable, as well as in electric cars that are increasing every day in popularity worldwide. They have the potential to deliver energy output that is extremely high in comparison to their minimal weight. There are multiple drawbacks involved in their use, however, and they include:
- Additional components, which are quite expensive, are required for pumping the oxygen gas in and out of a Lithium Oxygen Battery.
- This is accomplished with an open-cell configuration, which varies greatly from that of traditional sealed batteries.
- A lithium-air battery will waste a great deal of all injected energy as heat.
- They have also been found to be degrading fairly quickly during use.
- There is a major mismatch between the discharge of the batteries and its charging voltages. Every charging cycle results in serious power loss due to the fact that the voltage necessary for charging is 1.2 volts higher than the output voltage of the batteries.
- 30% of the battery’s electrical energy is wasted via heat loss during charging and, in fact, the battery could end up burning itself up in the event that it is charged too fast.
A New Lithium Oxygen Battery Concept
However, now a new concept in lithium-air batteries could overcome the many drawbacks and it is called the nanolithia cathode battery. It is a new innovative variation of the battery chemistry, which could be used in a conventional, fully sealed battery, and it promises similar theoretical performance as lithium-air batteries while overcoming all of the drawbacks. A traditional lithium air battery starts by drawing oxygen in from exterior air, which drives a chemical reaction during the discharge cycle in the lithium. That oxygen is released back into the atmosphere when the charging cycle creates the reverse reaction.
Energy Efficiency and Reduced Voltage Loss
According to a paper by the Battelle Energy Alliance Professor of Nuclear Science and Engineering at MIT, Ju Li, as well as several others at Peking University, Argonne National Laboratory, and MIT, with the new variation of the Lithium Oxygen Battery, the electrochemical reactions between oxygen and lithium still occur, however, the oxygen is never allowed to convert back to its gaseous form.
Conversely, it remains within the solid material, transforming between three redox states directly. But it still remains in the form of three solid chemical compounds that are very different from each other. They are Li2O2, Li2O, and LiO2, and they mix together in a gaseous form. When they do, they are reducing voltage loss from 1.2 volts to a decreased 0.24 volts, thereby a mere eight percent of the electrical energy of the battery turns to heat. And according to Ju Li, that equates to much faster electric car charging when the battery pack’s heat removal becomes far less significant in the area of safety concerns. In addition, he points out the fact that there are also the added benefits of superior energy efficiency.
Easily Adaptable
These new batteries are easily adaptable to battery packs designed for powering electronics, cars, and power storage that is grid-scale since installation and operation are the same as with a traditional solid lithium-ion battery. However, they don’t require the auxiliary components that are required by batteries with an older design.
Putting An End to Overcharging
According to Li and his team, the naturally self-limiting chemical reaction in the new battery prevents any further activity leading to overcharging when the reaction is shifted to another form. When you overcharge a traditional battery, it can be irreversibly damaged structurally. Li further stated that they had successfully engaged in overcharging a new nanolithia battery to one hundred times its capacity for 15 days without it ever incurring any damage whatsoever.
No More Electrical Conduction Path Disruption
Traditional lithium-air batteries have another issue that involves changes in volume causing a disruption of the electrical conduction paths, which can seriously limit the battery’s lifetime. This occurs during the chemical reaction created by the conversion of oxygen from a gaseous form to a solid form during the charge and discharge process. The new design creates minuscule particles in a cobalt oxide matrix instead to put an end to this particular problem.
Double Capacity
The future of these batteries seems to be that they are capable of being viable for a very long time. This was evidenced by cycling tests where a laboratory battery version underwent 120 hours of charging and discharging cycles, resulting in less than a two percent capacity loss. And, this new battery design can store twice as much energy for a specific cathode weight due to the fact that solid oxygen cathodes are considerably lightweight when compared to traditional cathodes. According to Li and his team, the new battery design can actually double again the capacity after the design is further refined.
Cheap, Scalable and Safe
And, according to Li, no costly materials or components were necessary to accomplish what they have done to date. The carbonate utilized in the battery for a liquid electrolyte is a very inexpensive kind. In addition, the component that is made of cobalt oxide has an overall weight that is less than half of a nanolithia component. All in all, this new battery is not only cheap but also scalable and ultimately a great deal safer than a lithium-air battery.
According to another expert in the field, Xiulei Jiwho, who is an Oregon State University Assistant Chemistry Professor, this breakthrough could be responsible for shifting the paradigm of the Lithium Oxygen Battery while also being compatible with the current infrastructure of mainstream battery manufacturing. Meanwhile, Li and his team are projecting that they will be capable of moving forward within approximately 12 months from the laboratory-scale concept proof all the way to an actual working prototype that is entirely practical in nature.
Sources
https://www.engadget.com/2016/07/25/lithium-oxygen-battery
