Apr 29 2019

Phosphorene Nanoribbons

As technology advances we find better and better ways to use existing materials. However, material science has the potential to introduce new materials to the equation, changing the game. It’s ironic that news about new materials tends to get relatively little attention in the media, but perhaps has the greatest potential to change our world.

That is exactly what I felt when I read this news about a production process to produce phosphorene nanoribbons. Sound boring, right? That’s why the popular reporting doesn’t even mention any of those things in the headline, but rather goes with the potential applications – We accidentally created a new wonder material that could revolutionise batteries and electronics.

As an aside, I don’t like the common narrative that something was discovered, “by accident.” The unspoken premise is that science is mostly looking directly for a specific effect or application. That is only a small subset of science, called translational research, where we are taking a discovery and looking to translate it into specific applications. However, the majority of research is just trying to figure out how stuff works. Often the findings of research are unexpected, and lead to new questions, and open up new possible applications. This is not “accidental” – it’s just part of the process. But the media loves that meme.

In any case, the actual paper, published in Nature, is not even about discovering the new material itself (which was discovered 5 years ago) but rather a process for reliably manufacturing large quantities of it with controllable properties. If you know anything about material science, that’s a huge deal, because most new wonder materials can’t get out of the lab because there is no way to mass produce them.

Phosphorene nanoribbons are “tagliatelle-like ribbons one single atom thick and only 100 or so atoms across, but up to 100,000 atoms long.” (Love the pasta reference.) They are made of phosphorous, which is an abundant element. Many 1 or 2-dimensional nanomaterials have been in the news over the last decade, most famously carbon nanosheets and nanofibers – 1 atom thick layers of carbon atoms which can be rolled into fibers. This class of materials is exciting because they have unique properties, such as strength (for their size), and electrical properties that can make them either incredible conductors or insulators, with low energy and heat dissipation needs.

Phosphorene nanoribbons are the same, but have additional desirable properties. The ribbons are extremely flexible while maintaining their integrity. They are also scalable, so you can make them in a variety of widths, lengths, and thicknesses. Further, they already exist in a liquid form that can be applied with ink-jet like technology. The ability to fine-tune things like thickness means that they can be used to join different materials with different dimensions, without having a hard joint that would block the flow of electrons.

The authors caution that we may have as much as 20 years of research ahead of us before we master this material sufficiently to see applications in wide use. But those applications have exciting potential. For example:

Perhaps the most important of these is in the area of battery technology. The corrugated structure of phosphorene nanoribbons means that the charged ions that power batteries could soon move up to 1000 times faster than currently possible. This would mean a significant decrease in charging time, alongside an increase in capacity of approximately 50%.

Of course I read about such things on a weekly basis. Most promised battery advances don’t come to fruition, but enough do that battery technology slowly progresses through incremental improvements that have added up over the years. Phosphorene nanoribbons seem likely to make their contribution (but of course we won’t know until they do). I have to say that often the biggest issue is mass production, so getting over that hurdle is actually a huge deal. There also doesn’t seem to be any hidden deal-killers, which is often the case with promised battery advances (Oh yeah, we need platinum to make the whole thing work, but the researchers plan to figure out how to substitute a cheaper material – then we never hear about it again).

The nanomaterial revolution is also coming at the perfect time (well, 20 years ago would have been nice, but I’ll take it). We are looking to change our energy infrastructure by adding renewable solar and wind power, and massive grid storage to make it all work. We need these advances. The more cost effective solar and wind can be the better. It needs to be cheaper than fossil fuel (it’s getting there, but every advance helps).

Actually the real limiting factor here is battery technology. Batteries need to be cheaper, lighter (for cars), with greater storage capacity, faster recharge, and greater life-expectancy. Imagine if every home and building had battery backup, for peak shaving (reducing peak demand), and also for backup power. This could then double for massive distributed grid storage. We may need to add some dedicated grid storage where needed, but then we could use the most cost and carbon effective power production all the time, regardless of demand. We also need to get to the point where having an electric vehicle is cost effective over a gasoline engine vehicle, without a huge upfront cost increase. Again, we are getting there with increasing mass production, but right now the limiting factor is the expensive batteries. Also, increasing the range of vehicles will help with “range anxiety” which limits some of the market.

In short, advances in battery technology will help virtually every aspect of the new green power infrastructure. Whether the batteries of the future are made with phosphorene nanoribbons or doped carbon nanofibers, or another similar material, is anyone’s guess. But it seems very likely these types of materials will take over. Of course, it can’t come fast enough. I hope it doesn’t take 20 years.

This is an area where there is a win-win that everyone should be able to agree on and benefit from. If we invest in a broad array of potential battery technologies, to accelerate their development as much as possible, we will be taking the lead on a critical technology of the future. This will help our economy, our technological leadership, create new jobs, and reduce pollution which helps the environment, improves public health, and may mitigate climate change. Even if you forget that last thing at the end – it’s a good idea. This is any investment that will likely pay for itself many times over.

As this study shows, the research is being done and is progressing. But timing is important when it comes to economic advantage, and in this case climate change.

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