Porous carbon, better batteries and working small to save the planet

As a nanoarchitect, PhD student Minjun Kim used to working small.

But like many of his peers at the Australian Institute of Bioengineering and Nanotechnology, the scope of his research is immense.

Minjun used science that could fit on the head of a pin to create “synthetic carbon” for smarter, better batteries for mobile phones and other smart devices.

This new carbon material is hollow, porous, honeycomb-shaped, and can replace traditional carbon due to its sophisticated structure.

Minjun’s discovery was published in prestigious journal Nature Protocolsalthough he is still months away from completing his thesis, with the work already available to other research groups to adapt to their own applications.

Minjun says his research in the Yamauchi Group is tied to his deep concern for the environment and ultimately was informed by the kind of world he wants to leave for his two young children.

“I would say as I get older and then see my kids, I think more about the future that I want to help create,” he says.

“Especially this year, I see so many natural disasters and a strange change in the climate all over the world.

“And we know it’s because of carbon emissions. We must therefore act and become a more sustainable society.

Read on to learn more about Minjun Kim, the incredible work he does, and how he hopes to save the planet.

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Minjun, you haven’t even completed your PhD and we are already seeing your work published in internationally recognized journals. What exactly is your research?

At the most basic level, I work with porous materials – any material that has pores or openings. I work specifically with porous carbon.

Porous carbon?

Yes that’s it. The good thing about carbon is that it has unique properties, such as high stability and structural integrity, it can be applied to almost any application we use in today’s world. It is also a conductor of electricity, which makes it usable in energy-related applications such as batteries and super capacitors. And when we make carbon porous – ie ‘activating’ the carbon – we open up a whole new range of applications.

Porous carbon effectively has a larger surface area and can contain a larger amount of reagents and adsorbents to influence the performance of various applications.

The problem is that the porous network is sometimes blocked or closed. Thus, the entire surface is not used in our desired applications. This is the challenge we want to take up.

What type of applications are we talking about?

Myself, I work specifically on energy storage and energy conversion applications. Carbon materials can be used for things like lithium-ion batteries. And it can also be used as an electrical material for super capacitors.

I look at carbonaceous materials as an electrical catalyst for fuel cells, which uses hydrogen to extract electricity to power something.

What attracted you to this field of nano-research?

I believe that our energy consumption is the most urgent thing we need to address. But it’s very hard. As the population grows, the demand for electric power will only increase, but since most of our energy still comes from fossil fuels, we will continue to see an increase in major global disasters if we don’t change. Climate change has made it clear that we cannot continue to produce energy as we have.

But then, even if we can generate a fair amount of electricity from renewable energy sources, if we can’t efficiently store that energy or convert it to another form for later use, we’re only addressing 50 % of the problem. So that’s what I want to help solve.

Level with us: we have a lot of work to do, don’t we?

Yes, we are still very far – at least in my opinion – from the truly sustainable society that we are aiming for. I think renewable energy consumption in 2021 was only 6.71% of total energy consumption. And energy derived from fossil fuels accounted for about 82%. This huge difference means we have a lot to do in terms of battery research and the like.

We also need to do more around hydrogen. Hydrogen does not produce carbon atoms. We split water to produce hydrogen. This is a technology that we have yet to implement: low-cost hydrogen energy. Research in this area still lags behind battery technology.

Do you hope we can improve storage and conversion? That we can accelerate the work that is being done in this area?

I think it’s difficult but it’s possible. Much research is published in the field of hydrogen-based energy sources.

The trick is going to be how we market it.

Take for example the type of application I’m working on, an oxygen reduction reaction catalyst, which is used in fuel cells.

The best electrochemical lever catalyst that we currently use is platinum which is, as everyone knows, very expensive. It is not abundant.

So if we can only use hydrogen, using platinum, even if it works, it will not be a good option to be widely used or marketed.

That’s why I work with carbon materials: to replace platinum-based catalysts with carbon-based catalysts. And then, by creating carbon with cheaper metals, like iron and cobalt, or even without the metal, we can achieve catalytic performance comparable to platinum, or even better than platinum.

Then we can talk about using cheaper catalysts to use hydrogen in fuel cells.

Would you say cost is the biggest hurdle for industry and businesses when it comes to transitioning their energy supply and storage?

Yes I think so.

It’s not just the individual batteries that cost money, it’s the entire infrastructure needed to make it work.

This is why the cost of new technologies is always high, because it takes a little time to integrate them.

That said, if we continue to work on this research and how we can use hydrogen, generate hydrogen, store hydrogen… I’m sure the cost of production, the cost of storage and the cost of fuel cells will eventually decrease.

And if it works, then we could really see better results with emissions, with energy consumption and with the environment.

Learn more about the Yamauchi group and their drum work hereand the JST-ERATO Yamauchi Materials Space-Tectonics project here.