Imagine a world where you never need to worry about finding somewhere to charge your phone's battery? The utopian dream of a long-lasting and sustainable battery might just be around the corner.
But is it realistic? Whilst we are not there yet, there has been a flurry of work by researchers around the world to make this a distinct possibility.
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Researchers and other scientists long-ago realized that if we are serious about moving to a more sustainable future we really need to fix the issue of limited capacity energy storage, like batteries. This has led to global discussions on the issue at hand.
There has even been an explosion in nimble startups dedicating themselves to the job. Their solutions range from incremental improvements on the ancient battery design to more out-of-the-box solutions.
To date, these range from micro-capacitors, miniatured solid oxide fuel cells, graphene polymer, aluminum-graphite, and gold nanowire technology and even sodium. There are batteries that can be charged by water, skin, sound waves, urine and plants and even salt and foam.
Yet, despite this explosion in ideas, none have yet been able to be commercially viable. At least, not yet.
One hurdle could be the lack of funds this area of research has managed to get. Lux Research, a technology research company, has estimated that of the 4 billion dollars spent on energy research, only 1% has been sunk into energy research over the last 10 years.
According to The American Energy Innovation Council, the United States, in particular, spends more on potato chip and tortilla varieties than on sustainable R and D.
Why we need to move away from lithium-ion
But what's wrong with lithium-ion batteries we hear you cry. This technology is widely available and relatively affordable for most.
But this belies the true cost of these diminutive power stores. Their production is far from sustainable.
Their component parts are often sourced unethically, from enormous mines and tend to be very damaging to the environment when they reach life's end.
As a matter of fact, Li-on batteries are not a recent innovation, despite what you might think. The technology can trace its origin to around 1912 thanks to the work of an American physical chemist Gilbert Newton.
But, it wouldn't be until the 1970s that non-chargeable Li-on batteries would hit the market.
Whilst today they come in a wide variety of sizes and shapes, their basic anatomy is virtually identical. Li-on polymer batteries, for example, only really differ from their other Li-on brothers and sisters by the use of dry solid polymer electrolyte.
Early chargeable Li-on batteries used lithium-based electrodes, but this was found to be less than ideal in the 1980s. They could become very hot indeed and could even be a potential fire hazard.
Today's batteries, on the other hand, replace lithium metal and instead use lithium cobalt for the cathode and graphite for the anode. The battery's electrolyte is also made of lithium salt.
The demand for lithium-ion batteries has led to a huge thirst for lithium the world over. So much so, that the price of it has doubled between 2016 and 2018.
One of the biggest sources of lithium is the so-called Lithium-Triangle that covers Argentina, Bolivia, and Chile. To extract it, miners drill holes in salt flats and pump salty, mineral-rich brine to the surface.
This is then left to simply evaporate in the sun and the lithium-rich salts scrapped up. But this process uses a lot of water.
So much, in fact, that local farmers really suffer for want of a decent amount of water for their crops. Not only that, but the process of extracting lithium can lead to the potential for toxic chemicals used in the process to leak into the local water cycle.
Disposal of them is also problematic for the environment. Whilst finding methods of recycling them effectively or finding other methods of extracting lithium from seawater could help solve a potential bottleneck in supply, it is only really a plaster on a broken arm.
We do really need to find an alternative to this venerable and ubiquitous battery.
What are some potential alternatives to Li-on?
To date, there are some interesting areas of research that could provide the potential for booting Li-on of its throne. The growth in electronics over the last century shows that the need for a long-lasting and sustainable battery is ever more pressing.
Other industries are also driving the impetus to get this sorted out as soon as possible. Electrical vehicles, in particular, will put even more pressure on dwindling natural resources and compound the already questionable practices employed in producing Lithium-ion batteries today.
Bearing that in mind, the following 4 areas of research could pave the way for a more long-lasting and sustainable battery of the future. There are many more projects out there, but these are some of the more promising.
1. Aluminum batteries would be better for the environment
One potential, from researchers at Victoria University of Wellington, is looking at a new type of electrolyte. They, in collaboration with Ecole Nationale Supérieure de Chimie de Clermont-Ferrand in France, could be the key to practical aluminum batteries.
According to research lead, Professor Thomas Nann, "This electrolyte will make aluminum batteries cheaper and easier to produce. It is more affordable than the ionic liquids currently used in aluminum batteries, and it is also more sustainable, as our electrolyte can be made from plants."
This could have legs. If achievable aluminum-based batteries would make an excellent alternative. They would be non-toxic, have little to no risk of exploding, be readily recyclable and aluminum happens to be one of the Earth's most abundant metals!
2. Adding molybdenum and sulfur to the mix could be the answer
Whilst not technically replacing lithium altogether, a research team at the University of Texas, are working on making the use of lithium in batteries more effective and safer for the environment.
According to the team, Lithium-sulfur batteries would be less expensive to produce, be very light and store more than twice the energy as traditional lithium-ion ones. But sulfur is a poor electrical conductor, electrodes of sulfur also tend to break down during charging - less than ideal.
But they managed to find a workaround. By adding molybdenum to sulfur, the electrodes suddenly become conductive and, more importantly, stable.
“This was what everyone was looking for, for a long time,” research member Dr. Kyeongjae Cho said. “That’s the breakthrough. We are trying to suppress side reactions. It’s a protection technology.
“We are taking this to the next step and will fully stabilize the material and bring it to actual, practical, commercial technology.”
3. Maybe we should re-invent the wheel completely?
Another alternative, by researchers at ETH Zurich and Empa in Switzerland, is looking at changing the materials used in the electrolyte and electrodes completely.
Titanium-nitride could be a good replacement for current lithium-based electrolytes. This is a ceramic-like material that happens to show high electrical conductivity.
Maksym Kovalenko at ETH Zurich said: “This compound is made up of the highly abundant elements titanium and nitrogen, and it’s easy to manufacture.”
It can also readily be formed into thin films.
Graphite is also readily used as the cathode in sustainable battery solutions like aluminum batteries. The team found they could replace graphite with a chain-like hydrocarbon called polypyrene.
Whilst this might sound like a strange choice, it has some interesting benefits over graphite. One of the most important being the ability to influence its properties.
The combination of titanium-nitride and polypyrene could open the door for something called 'pouch cells' which are batteries enclosed in a flexible film.
4. Sulfide electrodes could extend the life of lithium batteries
Researchers at the University of Central Florida have been working on a sulfide-based sustainable battery. In a recent report published in the Advanced Energy materials journal, they describe how they have designed a new type of electrode.
This electrode, they claim, shows excellent conductivity, is stable at high temperatures and should be relatively cheap to make. Not just that, but using it could make existing lithium batteries last much longer.
They estimate it could mean lithium batteries could retain their high-performance over thousand of recharge cycles without degrading.
Their solution is to replace the cathode with a thin-film alloy of nickel sulfide and iron sulfide. This combination brings the cathode many interesting advantages over conventional ones at between 300 and 500 times.
The secret is their combination of nickel- and iron-sulfides into a thin film. This film is later etched to make it porous at the nanoscale level.
These nanopores, or holey structures, greatly expand the surface area available for chemical reaction.
“This is really transformative thin-film technology,” Yang said.