Salt could save the world. A new battery technology is emerging, and it’s cheap. It could be the material that finally makes big batteries inexpensive and powerful.
You find sodium sitting right under lithium in the periodic table because they share similar chemical properties.
The way lithium ions function is essentially the same way sodium ions do. Sodium plays the same role in the battery, with the major downside being that sodium atoms are bigger and heavier.
“Manufacturing-wise, it’s a drop-in technology,” Deakin University’s Alfred Deakin Professor Maria Forsyth told Cosmos magazine in a recent interview.
Using sodium instead of lithium makes a battery less efficient per unit of weight, but much cheaper. Sodium can also make other parts of the battery easier to work with, including anodes and current collectors, making batteries even cheaper.
All these reasons are why a sodium-battery car has been unveiled in China in 2023 (made by JAC Motors, which doesn’t sell into Australia). Major Chinese manufacturer Chery (which does sell into Australia) has leapt on board too, pledging to use a sodium ion battery from mega-battery maker CATL in a new car soon.
While Western manufacturers may make tiny volumes of electric vehicles (EVs) for branding and regulatory reasons, China is pumping out millions. Its cost-conscious consumers have driven down the price and are a big reason for the rising EV penetration in Australia. BYD and MG are both Chinese brands — even the Teslas that Australia gets are all made in China.
The lithium problem
Lithium is tricky. It’s rare. Not as rare as gold, but rare. And it’s not available to every country. We have a lot, but China, not much. That is highly motivating when trade wars loom. Sodium, meanwhile, is everywhere and available to everyone.
Lithium is lightly concentrated in the earth’s crust. To mine a kilogram, you need to dig up an awful lot of ore. The world has 22 million tonnes of lithium which is sufficiently concentrated and close enough to the surface to be viable to dig up.
Let’s do the maths. There are eight kilograms of lithium in a small EV battery. So those 22 million tonnes could make almost 3 billion car batteries. However, there are 63 kilograms of lithium in a Tesla Model S battery, meaning that lithium would make only 350 million such batteries. That’s not enough.
Australia buys a million new cars a year. The world buys 60-75 million new cars each year, and rising. If all cars had Model S batteries we’d have enough lithium for six years. If all cars had small batteries, we’d have enough lithium for 60 years. Either way you can see a case for an alternative to lithium batteries.
The price is high
Lithium’s price has oscillated wildly recently, before settling at 200,000 yuan a tonne of carbonate (a salt form of lithium that is stable). At current exchange rates that is A$41,000 a tonne, or $41 a kilogram of lithium carbonate. Lithium carbonate is about one-fifth of lithium, by weight, so the price of pure lithium is about $200 a kilo.
But recently lithium carbonate prices have been as much as three times higher, as this chart shows.
You can see why a year ago it became vital to expedite lithium alternatives. The falling price of lithium since then is partly due to extra work by lithium miners to find reserves and exploit them. But to some extent it may also be an acknowledgment that alternatives have progressed.
We need more EVs
Australia is late to electric vehicle adoption. Only a few percent of new vehicle sales are EVs. We’ll have internal combustion engines on the road for a very long time. The reason people aren’t buying EVs is they are expensive. The cheapest new EV is about $40,000 compared with about $20,000 for the cheapest new petrol car.
Manufacturers need to figure out a way to make EVs cheaper if they are going to capture the bottom end of the market and chase cheap fossil-fuel vehicles off the road. That’s where sodium-ion batteries come in. They are heavier and less powerful per kilogram than lithium-ion batteries. But they can still play a role in many vehicles where power and speed aren’t so vital.
Lithium is not the only thing in a battery, but using sodium is expected to make batteries 30-40% cheaper. It’s easy to imagine a future with two tiers of EVs. Jaguars and Teslas will have lithium batteries and go like a rocket, eating up hundreds of kilometres before needing a charge. Meanwhile most people drive cheap Chinese EVs with smaller, cheaper, less powerful sodium batteries, an upside of which is they won’t blow up like lithium ones.
Sodium batteries can also do a lot of good work in stationary energy. It’s likely there’ll come a point where using lithium in batteries that don’t move around seems wasteful. Turning our renewables into reliable power depends on dispatchable, cheap storage. Sodium batteries could easily fill that role.
Sodium batteries are a much more realistic prospect than the recently floated plan to turn every farmer’s dam into a little hydro station. The sad reality of using gravity to store electricity is it’s simply not very efficient. You need large vertical distances, and preferably a substance much heavier than water to make it generate significant electricity at small scale.
The future is not in fresh water. It’s in the brine.
There’s still a $20,000 price premium for EVs, and that will last for some time if we’re stuck on lithium. Sodium offers the possibility of a two-tier battery situation in EVs — cheap, heavy EVs with sodium batteries and expensive lithium batteries for the most expensive cars. That’s not so different from the range of power options and fuel types in combustion engine cars, and is likely the answer to fully electrifying our fleet.
You say sodium batteries are less likely to explode. Why? The issue of lithium is that it is an extremley reactive metal as are all the Alkali Metal group. LIthium metal does not exist in nature. Sodium is even worse in terms of reactivity. Bot metals generate hydrogen and heat in the presence of water, one reason why lithium battery fires are seriously hard to fight. Sodium seems likely to be worse.
Yes, sodium is chemically similar to lithium, so it can be a cheaper substitute. But as the article points out, sodium batteries have lower energy density than lithium ones. This is a critical concern for in transport technology. Lithium battery vehicles are already much heavier than the equivalent internal combustion vehicles they replace. This takes more energy and more emissions in contructing the vehicles. They take up more space. They use more energy lugging that heavy battery around. They inflict more damage on road surfaces, which increases with the fourth power of the axle weight, so when a vehicle is twice as heavy it inflicts sixteen times as much road wear. (The money to repair the damaged roads often comes from fuel duty, but electric vehicles don’t pay that.) The vehicle emits no greenhouse gas, but the electricity used to charge the battery has to come from somewhere, and is seldom so clean. Because running an electric vehicle is cheaper (the capital cost up front is separate) it gives an incentive to use the vehicle more. Sodium battery vehicles will be significantly heavier again and worse in every respect, except for the much easier availability and cheapness of sodium compared to lithium.
Nearly all road damage is caused by properly heavy vehicles (ie: trucks, semis, etc). Even the heaviest passenger vehicles are largely insignificant from a road wear and tear perspective.
The average trip taken in Oz is in the low 20km, range anxiety is a thing made up by people who don’t want EVs to crush their ICE markets. As we get further down the AI path we’ll also need fewer cars. You won’t own your own
Probably the key point.
I suspect the biggest uptake in EVs from a family car perspective will be PHEVs with a 50-100km battery range. This covers the vast majority of daily driving in a single charge, without inducing range anxiety for longer longer trips. The added complexity is undesirable, but from an end result perspective it’s better than nothing.
Large vertical distances? Would an abandoned coal quarry suffice? The water is also already there at the bottom and the tailings dam at the top for high storage. We’ve got a heap of them in the Hunter Valley and the fossil fuel power delivery infrastructure to go with it… from the soon to be extinct Bayswater and Liddell coal fired power stations.
If you don’t like the use of water then how about lifting weights or spinning massive heavy wheels?
We really won’t solve the problem by just allowing everyone to change from ICE vehicles to EVs. Our cities are huge hot spots mainly because of the road infrastructure put in place to cope with the millions upon millions of private vehicles.
A serious transport rethink needs to be done. Our cities could fit so many more people in them if there were no private vehicles and only public transport.
But why ?
White roads?
Definitely need cheaper EVs. Smaller batteries even if a bit heavier for energy stored will mean less weight which means greater range for the energy stored. A road trip with a mandatory stop for a coffee length of time is not a bad compromise for a much cheaper EV.
Existing lithium batteries have a long life and can then be recycled into new batteries.
Long life – I am running 12 year old cells that provide daily service. Old chemistry and there is degradation but it’s a small cheap EV that still works for its intended purpose.
Recycling – this is essentially reversing the effect of the chemical and its containment ageing / change process. Because of long life we actually have a problem doing this efficiently / investing capital because there are so few to recycle (plenty of phone batteries I warrant).
If you need a car (maybe you don’t), then I recommend being realistic and buying for the majority of your use rather than the edge case. Then keep an eye out for an EV that will do that for the price you can bear. Maybe that is an electric bicycle!