Batteries Suck, But Nanotech can be Used to Make Better Ones
By: Elias Kountouris
Tags: Nanotechnology, Technology, Battery, MIT, Science

Batteries suck, we all know it. I don’t have to convince you about that.

The crazy thing is, they haven’t improved in a long time. Moore’s law is used to describe the increase in the number of transistors on a piece of silicon. It states that the number of transistors will double every two years, and it’s held fairly true.

Batteries don’t come close to following that. The average battery life has doubled once in the last 13 years. To be fair to all the battery researchers out there, this is technically an improvement, but it’s still been taking forever!

Crappy batteries are a larger problem than you may think. Here is the inside of Samsung’s Galaxy S10, a flagship smartphone:

That thing takes up half the phone!

Imagine how many more processors, sensors and other cool things you could squeeze in there if the battery wasn’t so huge!

How Batteries Work

The current in a battery is created by the flow of particles with a charge. In most batteries, the flow of lithium ions is what is creating the electricity.

Batteries have two electrodes. Think of them as containers. Every container is meant to hold something, and in this case, they are holding ions.

There is also an electrolyte, think of this as the path in which ions move around.

When you charge your battery, ions move across the path from one container to the other. They are then stored there until you use the battery. Once that happens they are then brought back to their original container.

The amount of charge a battery can hold is determined by two things, the number of ions in the battery and the number of ions each electrode can hold. Overtime both these numbers decrease over time.

It’s likely that almost every battery you have come across uses either this exact mechanism to store charm or something extremely similar. The unfortunate thing is that this method, despite its prevalence, has a ton of flaws!

A New Approach

One interesting approach done by researchers from the MIT Lincoln Laboratory and the MIT Department of Materials Science and Engineering is using nanotech to completely redesign how batteries work.

As explained, batteries use ions to hold a charge. In the majority of these batteries, this ion is lithium. While lithium ions offer a lot of advantages in terms of manufacturing and battery life, a big compromise that needs to be made is size.

Lithium isn’t everywhere. If you want your battery to use lithium ions you, therefore, need a source of lithium. So in most batteries, the electrolyte substance has lithium ions in it. This means that the battery life will be directly proportional to how much electrolyte is used and the concentration of lithium ions within the electrolyte. The problem with cramming more electrolyte into a battery is it makes the battery heavier and bigger.

If we want to make batteries smaller, we need to ditch the lithium ions in favor of something different. This is what the MIT researches have done. By replacing lithium ions with water, they can shrink the battery size tremendously.

Water vapor is in the air all around us. In fact, about 2% of the atmosphere consists of it. Water can also be split into ions, hydrogen, and oxygen.

The batteries the researchers made use a reactive metal casing, which when it comes into contact with water, splits it. The hydrogen ions are then stored, and this is what “charges” the battery. When the battery is to be used, hydrogen ions are released and bond with oxygen in the air.

This approach has allowed the batteries to achieve sizes down to 50 nanometers thick (near 1000th the size of a human hair). More significantly, the power density of these batteries (the ratio between how much power something can hold and it’s weight) is twice as large as most batteries.

This design allows for strong, small batteries that can be used for a wide variety of nano applications. So in the future, with new research like this shaking the battery industry, we may finally have batteries that won’t suck.