How sodium makes electric cars cheaper than lithium

HostWe usually think of salt as the stuff we shake onto a pile of fries, or maybe what we use to melt ice on the driveway. But lately, there's all this talk about using it to power the cars we drive, which sounds a bit like science fiction. I mean, we have been told for years that lithium is the only way forward for electric cars, so why is salt suddenly entering the race?

GuestIt's a pretty wild shift, but it comes down to a simple problem with lithium. We call it white gold for a reason. It's hard to find, it's expensive to dig up, and because everyone wants it at the same time, the price goes up and down like a roller coaster. Salt, or sodium, is the opposite. It's everywhere. You can get it from the ocean or mine it from the ground almost anywhere on earth. If we can swap lithium for salt, the cost of making the heavy battery pack in a car could drop by a huge amount, maybe thirty percent or more.

HostOkay, but if it's that much cheaper and it's everywhere, why are we only hearing about it now? I have this image of just dumping a box of table salt into a car battery and calling it a day, but I'm guessing it's not that easy.

GuestWell, you definitely can't just use the salt from your kitchen. It has to be processed and cleaned up first. The reason it has taken so long is that salt is naturally a bit bigger and heavier than lithium. Think of the inside of a battery like a busy hallway. In a lithium battery, the lithium bits are like small, fast runners moving back and forth to carry power. Sodium bits are more like big, bulky walkers. For a long time, they just couldn't move fast enough or fit into the spaces inside the battery without breaking things. We had to figure out how to build the inside of the battery with wider hallways, so to speak, so those bigger salt bits could move around without wearing the whole thing out.

HostSo it's a bit of a space issue. But if the bits are bigger and heavier, does that mean the whole car ends up weighing a ton more? I feel like that would just eat up all the energy you're trying to save.

GuestThat's the big trade off. You hit on the main reason why every car on the road isn't a salt car yet. Because the bits are bigger, you can't pack as much power into the same amount of space. If you want a car that can go five hundred miles on one charge, a salt battery would've to be massive and incredibly heavy. It would take up half the car. So, salt isn't really trying to win the long distance race right now. It's looking at the small cars, the ones people use to zip around a city or get to work and back. For those drivers, a cheaper car that goes maybe a hundred and fifty miles is a great deal.

HostI see where the friction is then. If I'm buying a car, I usually want to know I can take it on a road trip if I need to. Is a salt battery really a better choice if it limits where I can go? It feels like we're taking a step backward just to save some money.

GuestIt depends on how you look at it. If you live in a place where it gets really cold, salt might actually be a step forward. Lithium batteries hate the cold. They slow down, they lose power, and they take forever to charge when the temperature drops. Salt batteries are much tougher in the winter. They can keep their punch even when it's freezing out. And there's another hidden cost saver inside. In a lithium battery, you have to use a lot of copper for the parts that carry the current. Copper is really pricey. But salt batteries can use aluminum instead. Aluminum is cheap and light. So you're saving money on the salt and the metal parts around it.

HostThat's a detail I hadn't heard before. It's not just about the salt itself, it's about all the other expensive stuff you can leave out. But is this actually happening? It still feels like something that's five or ten years away.

GuestIt's actually happening right now. The first cars with these salt batteries are already rolling off the lines in places like China. They're small, affordable hatchbacks. They're not meant to be supercars, but they're proving that the tech works on real roads. We're also seeing big companies build giant salt batteries to store power for the electrical grid. When you're just sitting in a field storing wind power, you don't care if the battery is a bit heavy. You just want it to be cheap and safe.

HostSafe is a big word when it comes to batteries. We have all seen those videos of electric cars catching fire and how hard those fires are to put out. Is salt any better when things go wrong?

GuestIt's much harder to set a salt battery on fire. Lithium is very reactive, which is why it's so good at holding power, but it also makes it a bit jumpy. If a lithium battery gets poked or overheats, it can go into a loop where it gets hotter and hotter until it bursts into flames. Salt is much more stable. It's way less likely to catch fire if the car gets in a wreck. You can even drain a salt battery down to zero power for shipping, which makes it much safer to move around. You can't do that with lithium without ruining the battery.

HostIt sounds like we're looking at two different worlds. Lithium for the high end, long range stuff, and salt for the everyday, affordable cars that most people actually need.

GuestThat's exactly it. Salt makes the electric car something for everyone, not just a luxury item, because it uses materials we can find in almost any corner of the globe.

HostEven if it means those big salt walkers need a bit more room in the hallway, it's hard to argue with a car that's easier on the wallet and works better in a snowstorm.

GuestThe real win is that we're finally moving away from digging up rare metals in just a few spots on earth and turning toward a resource we have in every ocean.

HostIt's funny to think that the same stuff sitting in a shaker on your kitchen table might be the reason your next car is finally affordable.