If you're a regular viewer of vaguely science-based YouTube channels like this one
then you'll probably know only too well that we're living in a rapidly changing world
where some bright spark somewhere on the planet is coming up with a technology or device that
gets hailed as a game changer or revolutionary breakthrough almost every week. Most of them
don't end up changing any games or starting any revolutions though, but every now and then
science hits the jackpot and the world takes another technological leap forward. Way back
in 1959 the American physicist Richard Feynman gave a talk in which he described his vision
for one of these winners. It was a process that would allow scientists to manipulate and control
individual atoms and molecules. That might not sound earth-shattering to our 21st century ears
but it was pure science fiction back then. Feynman's dream became a reality in the 80s though
with the advent of something called the scanning tunneling microscope for which its inventors,
Gerd Binning and Heinrich Rohrer received the Nobel prize for physics in 1986.
That invention allowed scientists to do precisely what Feynman had envisaged more
than two decades earlier and the world got a fancy new word to add to the dictionary...
nanotechnology. Since then nanotechnology has genuinely revolutionized almost every
aspect of our modern day lives from pharmaceutical products to construction materials and industrial
processes through to fuel efficiency and even the clothes we wear. And now nanotechnology has
reached the world of electric vehicle batteries and needless to say it's gonna be a game changer!
Hello and welcome to Just Have a Think. So we know that nanotechnology is to do with atomic
and molecular scale stuff, which means we're talking small right? I mean really small. A
nanometer is a billionth of a meter. A human hair is about a hundred thousand nanometers wide so the
ability to manipulate stuff at nanoscale is pretty spectacularly smart science. And it turns out when
you get down to that kind of microscopic level weird stuff happens. Atoms start reflecting light
differently for example, so gold can become purple and silver can become yellow "and your mommy
suddenly becomes your daddy, and everything looks like a giant cupcake". Perhaps more significantly,
getting down to Nanometer scale allows scientists to vastly increase the surface area of a material
which means more atoms can interact with atoms of other materials. And then all sorts of benefits
start kicking in. You get materials that are stronger, more durable and even more
electrically conductive as a result. According to the US National nanotechnology initiative
"Nanotechnology is not simply working at even smaller dimensions. Rather working at nanoscale
enables scientists to utilize the unique physical chemical mechanical and optical properties of
materials that naturally occur at that scale." The potential of nanotechnology certainly hasn't
escaped the attention of the auto industry and in particular the rapidly developing electric vehicle
sector which has spent years and years looking for ways to reduce weight and improve the performance
of vehicle batteries. Much has been promised by so many but as is so often the case these days it's a
Chinese company that'll be the first to launch an actual vehicle onto the actual market that
actually contains nanotechnology in its actual battery. They're called GAC group and they're
about to launch the latest version of their Aion V crossover SUV featuring lithium-ion batteries
enhanced with graphene, which is a nanomaterial that China is particularly obsessed with.
Specifically GAC's technology uses graphene instead of graphite as the anode material.
Graphite's the usual choice for lithium-ion battery anodes because it easily transfers
collected electrons into the metal wires of an electrical circuit but it does have its
limitations. It takes six carbon atoms in graphite to hold onto a single lithium ion.
That relative weakness limits how much lithium the electrode can hold onto which in turn dictates how
much potential energy the battery can store. Studies over many years have shown that unlike
a lump of graphite a graphene nanosheet can absorb lithium ions on both faces of the sheet and along
its edges and even in any defect sites. That gives it a theoretical capacity of 744 milliamp hours
per gram compared with only 372 milliamp hours per gram for graphite. That's twice the capacity which
is really very significant indeed. The main limiting factor until recently has been cost.
At several hundred dollars per gram, graphene is still a premium product. Until we find a way
to mass produce it in a more economical way it'll probably be limited in its real world
applications. But GAC group have come up with a technology called 3DG or 3-dimensional graphene,
which they reckon reduces the graphene cost in their lithium ion battery anode by a factor of 10,
which brings graphene firmly into the realms of feasible production budgets. GAC say its graphene
based battery has a 6C fast charge capability. In other words it's capable of receiving 6 times its
total capacity in an hour, which is significantly higher than any existing EV on the market today.
Charge and discharge rates in batteries are often expressed using this C rate figure.
The higher the number the greater the charge the battery can accept for its given capacity.
The downside with very high C rates is that they tend to generate high temperatures
which can quickly degrade the materials inside the battery. And that's really
one of the main limitations holding back the development of super fast charging for EVs.
Graphene is much better at accepting those higher charges without degradation though, and
although GAC haven't provided specific technical details of how their 3DG tech works, it's quite
likely that it's this property of graphene that's allowed them to achieve such high charge rates.
The result is the new Aion V can be recharged from zero to 80 percent in just eight minutes. That's
getting much closer to the time it takes to fill up an internal combustion engine car with a tank
of fuel. GAC aren't the only ones to have embraced a nanotechnology solution for their battery tech
though. Mercedes-Benz recently announced a joint partnership with the U.S company Sila
Nanotechnologies, to develop a battery for their G-class SUV that replaces the graphite in the
anode with silicon nanoparticles. The principle is not dissimilar to the graphene that GAC have used.
A silicon atom can bind to four lithium ions which in principle means a silicon based anode
could store 10 times as much energy as a graphite anode. Silicon is very cheap and very abundant
so there's a big commercial advantage there over graphene. The trouble is as the battery charges up
all those lovely lithium ions rush in to bind with the silicon and the anode swells up by as much as
300 percent and then it shrinks back down again as the battery discharges. That's an awful lot of
movement fatigue and it means most developmental silicon anodes quickly fracture and break down
making the battery useless. But once again the weirdness of nanomaterials has come to the rescue.
They have much higher percentage of their atoms at the surface relative to the number of atoms
in their interior and because those surface atoms have fewer atomic neighbours locking them in place
they can move much more easily to respond to the stresses and strains of expansion and contraction.
It's a bit like why aluminium foil can be bent and scrunched up very easily
compared to a thick lump of the same material. Sila's silicon nanotechnology is, they tell us,
the result of more than 10 years of chemical research and more than 55 000 iterations,
the result of which is a battery with an energy density of more than 800 watt hours per litre.
Now I don't know about you but I'm more used to reading about battery energy in terms of
watt hours per kilogram so I had a quick look at Battery University online and it explains that
specific energy or gravimetric energy density defines battery capacity in weight, which is
indeed watt hours per kilogram, but energy density or volumetric energy density reflects volume in
litres. Whichever metric you choose to focus on though, the important thing is the relative
performance between different battery chemistries. Sila's website provides this chart showing the
limit of today's lithium-ion batteries and how their technology will vastly improve things in the
coming years. Mercedes-Benz are aiming to launch their new G-Class range with as much as 40 percent
more battery energy density as soon as 2024 and I reckon we can expect to see a whole raft of other
manufacturers following suit very quickly. And as an added bonus Sila reckon these batteries
will be manufactured using 100% renewable energy at their brand new Washington state facility.
I think it's fair to say we're still very much in the wild west territory of the electric
vehicle development cycle. New chemistries and concepts are popping up all the time,
all claiming to be revolutionary game changers of course! Will you be charging your EV in under 5
minutes in 10 years time or simply topping it up as you drive along via inductive charging plates
under the road surface? Or perhaps you'll simply drive into a kiosk when your battery is dead
and wait while a robot swaps it out for a fully charged one. Maybe we'll end up filling our
cars with hydrogen instead and perhaps we won't even own our own vehicle in the coming decades
and we'll just tap on an app and wait two minutes for an autonomous vehicle to arrive
and take us to our destination. All of these technologies already exist. It's just a matter of
which one gains market supremacy the fastest. For someone like me who is now well into middle age
it feels like the world has changed beyond recognition since I learned to drive in a
crappy old Nissan Micra more than three decades ago, but based on what's going
on in the tech world right now, hold on to your hats folks because you ain't seen nothing yet!
No doubt you've got views about these rapidly developing technologies.
If you do, or if you work in the industry and you can share some insights with us,
then why not jump down to the comments section below and leave your thoughts there. That's it for
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