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Modulus.

If I was to ask you today what technology breakthrough the world needed most right now.

What would you say? This needs to be a technology that we could realistically develop in the

next 10 years. So none of that sci-fi non-sense. This is something I think a lot. Nuclear Fusion

or cheaper, safer and cleaner fission energy are good candidates. Human society would be

transformed by economic fusion power, but fusion is most certainly not a technology

that can be commercialized in the next 10 years. Many people are working on safer and

cheaper nuclear fission, but that too has many hurdles to overcome. I think about how

the world would change if carbon nanotubes somehow became a viable material. A new stronger

and lighter material of carbon nanotubes calibre wouldn't open doors to new design possibilities,

it would open portals to new dimensions. But that again is not going to happen any time

soon. No, if I was to pick one technology that would have the biggest impact on our

society today, that is within grasp, it would be cheap, scalable energy storage for the

grid.

The electricity grid works nearly entirely on a just in time manufacturing method. We

generate the electricity just as it's needed. There is no warehouse of electricity that

we can dip into.

Pumped hydroelectricity does provide some storage and is a nearly century old technology,

but is not scalable to our current needs.

Lithium ion batteries are our best option right now. They have proven their worth in

the Hornsdale Power Reserve in Australia. It was commissioned primarily as a fast frequency

response service. [1] This means it can act as both a load when the frequency of the grid

gets too high, or as a power source when the frequency of the grid gets too low. Kind of

how a flywheel maintains the rotational speed of an engine.

You see our grids are designed to operate a particularly alternating current frequency.

If the grid deviates from that frequency, it can cause all kinds of issues that generally

just result in protective measures being activated to protect the infrastructure, and ultimately

cuts power to it's users. A blackout.

South Australia was struggling with these blackouts.

In 2016, tornadoes ripped through South Australia and damaged some power lines. This caused

the voltage and frequency of the grid to deviate from its baseline. [2]

This caused the wind turbines to trip their protective measures and lower output. Now

this was a massive problem because this is what South

Australia's power generation looked like on that day, with nearly 50% of their power

coming from wind. [3] To deal with the sudden decrease in output in wind the interconnector

to Victoria attempted to increase its power transfer, but rather quickly shut itself down

to prevent the line frying itself.

The grid basically did the technological equivalent of a human passing out when seeing a drop

of blood. A chain reaction of panic. Leaving 850,000 people without power.

In response, the Australian Energy Regulator is trying to sue the wind companies it had

approved for not doing a job they were not capable of doing in frequency regulation.

[4] I feel like they only have themselves to blame. South Australia had built far more

wind power than it's grid could reliably handle. It lacked the necessary interconnections

to neighbouring grids and energy storage facilities like pumped hydro, batteries, or simply reserve

power natural gas plants. It was a poorly planned grid. Instability was inevitable.

We are thankfully learning from these mistakes, but as renewables grow the challenge of preventing

blackouts like this is only going to grow. We won't just need fast frequency response,

but we will also need load shifting. Where we have enough storage to charge batteries

when renewables are available and discharge them when it isn't. This is going to be

expensive.

Lithium ion batteries are the cheapest we have right now, but when it comes down to

it, they weren't designed for this job.

They are designed to be light and energy dense for portable electronics, but for a stationary

battery that's a pretty useless trait to have. It's like having an underwater hair dryer.

Just doesn't make sense.

Lithium ion batteries are the cheapest form of energy storage available because their

mass market adoption has allowed for the economics of scale to reduce their price, but what if

we designed a new type of battery. A battery that was designed from the ground up specifically

for the grid. To learn more about this, I spoke with Donald Sadoway, a renowned professor

of materials chemistry at MIT and founder of liquid metal battery company Ambri.

Cut to Prof Sadoway interview:

The last thing I do is seek the advice of the incumbents. The incumbents are threatened

by radical innovation. You realize that the lithium ion battery did not come from the

battery industry. The battery industry refused to even manufacture the lithium ion battery.

So Sony, Sony wanted a better battery to power their handheld devices

And this is 1990. And Sony goes to all of the big battery producers in Japan , And they

go, and they say, here's the here's the formulation, build this. And here's a purchase order for,

pick a number, some 10s of millions of dollars. And each and every Japanese battery manufacturer

said, “No, I'm not building that.” “We have all this capital investment in the manufacture

of nickel metal hydride batteries. We can't build this battery in that plant.” And so

they said no.

And somebody at some point said, you know, if we want to have lithium ion batteries for

appliances. There is only one way we are going to have them. We're going to build them ourselves.

And Sony says “We aren't a battery company” says, “We need batteries. And there's only

one we're going to get them we're going to build them ourselves. And so Sony built the

first lithium ion battery manufacturing facility.”

And very soon thereafter, they were getting inquiries from people who are building mobile

phones, saying can we have those? And then people who are building mobile computers,

laptop computers, can we have those? And by 1995, nickel metal hydride was pretty much

displaced.“

So what battery chemistry is Prof. Sadoway is trying to build and can it have the same

revolutionising disruptive effect on grid storage that lithium had for consumer electronics?

The idea started simply. Professor Sadoway had decades of experience in electrolysis

refining for metals like iron and aluminium. That process takes a lot of energy to refine

the metal. Why not try to make that process reversible and allow the reverse reaction

to give electricity back.

This is the basic concept of liquid metal batteries. We alloy and de-alloy metals in

a perfectly reversible reaction. They don't need to be light. They need to be cheap. And

as Prof. Sadoway says

“I say, if you want something to be dirt cheap, make it out of dirt”

So how do we go about choosing materials for a battery like this? What does the design

ideation phase look like? Professor Sadoway is a professor of Materials Chemistry at MIT.

Looking at a periodic table is a different experience for him.

This is what he sees when picking materials for a technology like this. For the liquid

metal battery, we first need to refine our search down to metals and metalloids, which

are these elements.

Next, we need to maximise the difference in electronegativity to maximise our voltage.In

general, electronegativity is highest on top right of the periodic table and lowest on

the lower left. So, our electrode materials can be further narrowed down to elements in

these two groups. [5]

Next, as Prof. Sadoway said, if we want our battery to be dirt cheap, we have to make

it out of dirt. So let's plot our relative abundance of elements. [6]

Of the candidate elements for our negative electrode, Calcium is by far the most common.

Which is the negative electrode for the Ambri Liquid metal battery. However, they didn't

arrive at their current electrode materials just by analyzing the periodic table. Experimentation

was vital as this is a complex and dynamic system. They have tested several combinations

of different electrode materials from these two groups, and there are a lot of complicated

interactions to consider. [7]

Ambri has landed on a Calcium Antimony cell chemistry. So how does it work?

These materials are placed into a ceramic insulated cell together. When a current is

applied the materials begin to heat up. Eventually they will turn liquid and the metals will

separate naturally as a result of their density differences. The heavier positive electrode

sinks to the bottom with a neutral density electrolyte separating the lower density negative

electrode on top. This makes building the cell very simple. Lithium ion batteries use

complicated coating processes to build their electrodes.

This is the charged state, now when a load is applied the opposite electric current is

experienced. This causes the calcium electrode to break into a calcium cation and 2 electrons.

The cation travels across the electrolyte bridge and combines with the antimony and

the electrons that have travelled on the external circuit to form a new alloy. This continues

to happen until the calcium electrode is completely consumed. Now we just have the new mixed alloy

and the electrolyte. This is the discharged state. To get back to the charged state we

simply apply the opposite current and the reverse reaction occurs and creates a fresh

battery.

Now this brings another advantage. Lithium ion batteries degrade over time. As they are

charged and discharged, chemical reactions occur that damage the electrodes and reduce

their ability to hold a charge, and many of the ways we need a load shifting battery to

operate are the exact ways that accelerate this degradation over time.

Taking a lithium ion battery from full to zero charge is particularly damaging. As few

as 500 deep cycles, can reduce the capacity of the NCA batteries that Tesla uses by as

much as 20%. [8] That represents about a year and 4 months of daily use for our load shifting

battery, whose job will be a daily one.However LFP batteries, which Tesla has started using

in it's Chinese Model 3s, degrade much slower even under deep cycling and they have stated

that they will use LFP batteries for stationary storage in the future. Depending on the temperature

they operate at LFP batteries drop to 85 to 95% capacity after three thousand cycles.

Higher temperatures result in higher capacity drop.

However, Ambri have shown that their capacity fade is minimal even after 5000 cycles [9],

thanks to the continual creation and destruction of it's electrodes. Allowing us to fully

discharge our batteries on a daily basis for upwards of twenty years.

However, as I'm sure you have been wondering, keeping the calcium and antimony electrodes

so hot that they melt comes with disadvantages. For one, we are going to lose some of our

electricity to heating the materials up to operational temperature. This reduces our

round trip efficiency.

So, to explain it, if you put 100 units of electricity in, there are some losses because

there's some joule heating, and so on and so forth. With liquid metal battery, it's

about 80%. Because the difference, the 20% is the energy lost desirably to heat the battery

to keep it at temperature. So you say wow, 80%, that's 20% loss. What's up with that?

The round trip efficiency of pump hydro is 70%. So we're better than pumped hydro. But

the thing is that this is a case of don't don't answer irrelevant questions, because

the key question is, what is the cost of electricity.

So this is where things get a little complicated, luckily we have an equation to calculate the

levelized cost of electricity storage. [10] It's determined by the total costs, which

are the sum of the initial capital cost, the continual operations and maintenance cost,

the cost of charging and the end of life costs, divided by the total electricity discharged.

Based on Ambris calcium-antimony cell chemistry, the cost of electrode materials vastly undercuts

current generation lithium ion batteries. With the total cost of the liquid metal battery

electrode materials coming in at 17 dollars per kiloWatt hour versus 51.2 dollars per

kiloWatt hour for the most common nickel manganese cobalt batteries. [11]

If they manage to get the initial capital cost down 66%, that decrease in round trip

efficiency is a minor concern.

These continual costs are hard to predict. Operations and maintenance costs for lithium

ion batteries could include buying more batteries to bring total capacity back in line as the

batteries fade. We also have very little data for end of life costs, which will primarily

be determined by how easily disposed of or recyclable the batteries are. For both of

these metrics, liquid metal batteries will likely have an advantage.

However, even with the promise of liquid metal batteries, Lithium ion batteries have a major

leg up on any potential competitors. They have had decades to work on the manufacturing

process and reduce their price, and they are still getting cheaper.

Ambri have proven this cell chemistry works on the bench scale, but actually bringing

a product to market is much harder than proving the science works.

“It's simply the the long journey from lab bench to, to marketplace. We, you know, here

at MIT, I with my my team of students and postdocs, we worked on this. I had a concept

and then we we reduced it to practice and then got it to the point where we said it's

time to start a company.Now, how do you take that and turn it into a marketable product

that is able to be manufactured? At the university, you know, you make five cells and one of them

works and you get a publication out of it and everybody's high fiving and so on. But,

but in manufacturing, you have to have, everything has to work. So, so we had to design the manufacturing

process. And there's nobody to turn to there's no there's no model. I can take the most brilliant,

the most competent people in the lithium ion battery sector. And almost everything that

they know is in applicable because they're the lithium ion chemistry is different, which

means that the format of the battery is different. their needs are different. I mean, they have

to guard against thermal rise, we have to guard against thermal fall. We want to keep

our batteries hot, they're trying to prevent their batteries from getting hot.