Batteries, you and me!!

I was born in Colombia in 1992 during a historic drought. Most of the energy in Colombia comes from water dams, so the drought caused massive energy shortages. Fast forward twenty years later, I find myself immersed in and intrigued by the world of nanotechnology. What I found so attractive about nanotechnology was the ability to make things that were a thousand times thinner than my hair. Better yet, I learned that you can use those tiny things to save the world from massive energy shortages.

The world produces much of its energy from burning fuels. When you burn those fuels, you release gases into the atmosphere causing air pollution and global warming. Beyond these problems, we know that those fuels will not last forever: you use them once and then they are gone. So, unless we do something, we will have massive energy shortages in the future. Scientists and engineers all over the world are coming up with solutions. In my opinion, the smartest solution is to use the energy from the wind and the sunlight to power our future.

To take the energy from the wind and the sunlight and turn it into useful things -like powering your phone- you need wind turbines and solar panels. These technologies are replacing the old fuels in many parts of the world. The big question with this alternative is what to do when the wind is not blowing or the sun is not shining? Batteries are the answer to that question. Batteries can take that electricity and save it for later use. This is what makes them so convenient to store electricity in phones, laptops, and electric cars. Today, batteries are still not good enough for everyone to drive an electric car or for the world to run on the power of the sun instead of old fuels.

Here is where saving the world, nanotechnology, batteries and I come together. A few years ago I was super into solar energy and wanted to use nanomaterials to make solar cells. As the good scientist and engineer that I am, I read a lot and learned that storing energy was the bigger challenge. Energy is not something you can just pour into a tank and then drain it. To store energy in a battery, you need special materials that can change when you put energy in and can change back when you take the energy out. All of these changes happen at a scale so small that you need the tools of nanotechnology to observe them and engineer them.

I was so intrigued by this challenge, that I decided to learn more about it in grad school. Four years ago, when I started my PhD, my knowledge on batteries was about as good as yours. All I knew was that they were everywhere in all of my electronic devices: the phone in my pocket, the laptop in my backpack, the alarm-clock on my night table. That was me in 2016, I bet you should have more batteries now than I did back then. So many batteries around, and so little did I know of how they worked.

After all this time, I finally found a simple answer that satisfied my curiosity. Here is how batteries work. Your phone’s battery is made of three key components: a negative side, a positive side, and a liquid in the middle. What happens when you use your phone is like a game: tiny lithium balls go from the negative side to the positive side traveling through the liquid in the middle. Guess what happens when you charge your phone? The same tiny lithium balls leave the positive side to go back to the negative side of the battery. The more balls you can move around, the more electricity you can keep inside the battery.

I hope you are asking yourself two questions: 1) why do I have to charge my phone everyday? 2) What are scientists doing to make the charge last longer? I got answers for you. The number of lithium balls in your battery depends on the materials of the positive and negative side. The limit today is the material of the negative side: it is made of graphite, the same material of the tip of a pencil, and it can only keep enough lithium balls for about one day worth of charge. The nice thing about graphite is that you can put lithium balls in and out thousands of times without a problem.

To answer the second question, let me brag about my PhD. At the beginning of my studies, I worked on a new type of material for the negative side. What is cool about this material is that it can keep almost ten times more lithium balls than graphite. The one problem with this material is that it breaks when you put lithium balls in and out. If it breaks, your battery stops working. In order to make this material sturdier, we have to understand it first. What I did as part of my thesis was to watch how the material breaks in real time using X-rays. The things we observed at the nanoscale are helping engineers design this type of material in a way that it will not break when you put lithium in and out. When we figure this out, you will have to charge your phone once a week instead of everyday. How cool would that be?

Charging your phone less frequently will be just a small victory for battery scientists and engineers. The real victory will be to enable a world powered by the sunlight and the wind instead of dirty fuels. In the end, it is energy what connects batteries, you and me.

Want to learn more?

Watch this 3 minute video of me explaining another cool way we are trying to make the charge of your phone last longer https://www.youtube.com/watch?v=3XweE0g7skc&t=102s

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ADDENDUM:

I want to thank Simón Montoya Bedoya (@SimnMontoyaBed1) for noticing that I had originally described charge and discharge backwards. I guess after so many years and almost with a PhD I am still allowed to make mistakes.