Future smartphones may charge faster and last longer thanks to supercapacitor technology
So basically, that's what a capacitor is – a device that can store and deliver electrical charge. This makes it similar to a battery, which has the very same application. Then why do all smartphones use batteries instead of capacitors? Well, that's one of the questions I'll answer in the paragraphs below. But the main focus of this article is on supercapacitors – a relatively new yet increasingly popular type of charge-storing device – and on why these might one day replace the ubiquitous lithium-ion battery cell.
Batteries vs capacitors: what's the difference?
Batteries come in many shapes, sizes, and types. The ones that all modern cellphones use are rechargeable lithium-ion batteries, which are known for their high energy density. This means they can store a lot of charge in a battery unit that's small and light, which makes them perfect for use in portable electronics.
Unlike batteries, capacitors have the ability to charge and discharge extremely quickly, which makes them great for zapping students in physics class. On the other hand, they store a very tiny amount of charge for their size. If a capacitor with the energy capacity of an iPhone's battery was ever designed, you'd need a van to move it around. These are just a few of the many factors setting batteries and capacitors apart, but they're enough to give you an idea why a common capacitor can't power a smartphone.
So what are supercapacitors then?
The properties of existing supercapacitors (also called ultracapacitors) put them somewhere between batteries and regular capacitors. They can store a reasonable amount of charge – still far from what a battery can hold, but a hundred times more than a capacitor of the same size. Also, supercapacitors can be charged much faster than a lithium battery, won't degrade as quickly over time, and have greater tolerance for extreme temperature.
Current supercapacitors can't replace the battery inside a smartphone, but advancements in the field could make that a reality one day. Imagine a smartphone battery that charges in seconds and performs like new even after a decade of use. That would be awesome, no doubt about it.
What's the future of supercapacitors?
One thing's certain: next year's flagships won't be powered by a supercapacitor, as a contemporary supercap of practical size can't hold enough charge. Actually, we could be a decade or more away from the launch of such a phone. But research is being done by a number of institutions with the goal of discovering ways to increase supercapacitors' energy storage abilities. One of the teams working towards the goal is at the University of Central Florida and recently published an article highlighting their progress. And their research results sound optimistic: the team has developed a new process for making supercapacitors with higher energy density. This has been achieved through the use of nanomaterials – conductors 100,000 times thinner than a human hair – for storing and transferring charge. On top of that, UCF's supercaps are flexible and can endure 30,000 recharge cycles without failing.