Dipping batteries brings more power

We all know the rule: Liquid and electricity don’t mix. Not only is it dangerous, because of the risk of electric shock, but mixing liquid with consumer electronics is also ruinous.  So, when Stanford University researchers proposed “dipping” ultracapacitors into a polymer to increase their storage capacity, that caused a bit of a pause. However, Stanford’s idea of dipping has nothing to do with water or commonly used liquids.   Instead, the idea from Stanford researchers involves coating the ultracapacitors with a material that can increase the ability of the units to store energy.

 

The materials the researchers are using contain ions that can carry a charge, which, when coupled with the original materials, result in better ability to store power.   Ultracapacitors technically aren’t batteries, even though both types of devices store energy. An ultracapacitor (sometimes called a supercapacitor) stores much less energy than a battery, maybe about 10%, but it can release that energy much more quickly than a standard battery, and it can be recharged over its lifespan many more times than a battery.

 

Ultracapacitors primarily appear in commercial applications, such as momentary-load devices and uninterruptible power supplies in electrical power systems or in electric vehicles.   Even though ultracapacitors may have some fundamental differences from batteries, they show enough similarities that some of the researchers’ work could migrate between the two types of devices.  

 

The Stanford researchers, led by Yi Cui and Zhenan Bao, performed two steps to increase the storage capacity of the ultracapacitors. First, they came up with some different materials – graphene and manganese oxide – to create the composite electrodes that store the power in the ultracapacitor. Despite a relatively low cost and some promising properties, manganese oxide hasn’t been used in the past for ultracapacitors, because it has a poor conductivity.   However, the researchers were able to overcome that problem through the dipping technique, which improves the conductivity and increases the storage capacity of the manganese oxide.

 

The researchers actually found two dipping solutions that provide the desired benefits, a conductive polymer solution and a carbon nanotube solution. The conductive polymer was more effective in increasing storage capacity, by about 45% in the initial tests, but, because of the commonality of carbon, it could be a less expensive option over the long haul.  

 

Showing the ability of manganese oxide to have a greater conductivity is an important aspect of the research, as many people have been looking for inexpensive materials for ultracapacitors. However, the key consideration with this Stanford research is the development of the dipping technique. (To see a drawing of the molecular changes that take place during the dipping technique, visit this Stanford research Web page: http://www.stanford.edu/~ghyu/Research.html and scroll down to option number two.)  

 

Keep in mind that Stanford’s research isn’t focusing on the general kinds of batteries all of us use every day, at least not yet. However, soon after the announcement from Stanford, other researchers latched onto the idea of using a similar dipping technique with rechargeable batteries. For example, the dipping technique could work with common battery storage materials, such as lithium-ion, according to some researchers.   If this technology eventually trickles down to consumer batteries, the usability of laptops and smartphones would change dramatically.

 

This type of technique could also improve the overall lifespan of rechargeable batteries by giving them the ability to recharge far more times than today’s batteries.   Of course, it would also eliminate the excuse of not answering a call from your boss because your smartphone battery was dead. With far more powerful batteries, you’d perhaps have to move to a more extreme excuse, such as “accidentally” dropping your smartphone in a puddle. After all, researchers still are quite a ways away from making electricity and water mix successfully.