Top 5 New Battery Technologies to Follow in 2024

Developing reliable energy storage is just as, if not more, important as improving methods of obtaining the energy itself. But among the slew of new batteries and energy storage systems, how can you tell which tech is worthy and which is just hype? Well, let’s break down what battery tech innovations I find personally interesting along with the scientific grounds to back my perspectives up.

Right now I’m watching a handful of technologies that run the gamut from making energy storage dramatically cheaper to super energy dense batteries for the EVs, home energy storage, and consumer electronics of the future. So, what kinds of batteries am I keeping an ion?

Sodium-Ion

One of the bigger issues with modern batteries is their use of critical minerals like lithium. Its relative rarity drives up its cost, and the easiest way to extract it is by mining, which isn’t conducive to protecting nearby populations or the environment.¹ So what if we could swap out those rare metals for something so common it’s probably in your kitchen right now?

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That’s the idea behind sodium ion batteries (or SIBs). Salt is relatively cheap and 1,400 times more abundant in the earth’s crust than lithium. It’s easier and less expensive to extract and purify salt for battery use, too, so you’re looking at what should be pretty cheap battery.²³ And luckily, salt functions similarly to lithium, so the working principle behind a SIB should sound pretty familiar to anyone who knows their ways around a standard lithium-ion battery. Anode, cathode, separator, the whole nine-yards. The difference is this cathode is made of sodium, and thus sodium atoms are shuttling around.²³

Of course, there’s a reason why we’re still using lithium batteries. Salt is notably less energy-dense than lithium, necessitating bigger batteries. So salt’s probably never going to replace lithium in the high performance world of electric cars. But if we can find a way to boost SIBs’ performance? Then we’d potentially have cheap, safe, and plentiful batteries that would be a great fit for our growing stationing storage needs. This has led scientists like those from Humboldt-Universität zu Berlin (HBU) to look for ways to push their capacity even further.⁴⁵ And they just recently published research on an unexpected discovery that has the potential to do just that.

To increase the capacity of SIBs, we have to increase their stability, and one promising way of doing that is through a process called “doping.” It’s not what it sounds like. This is a technique where the electrode is very lightly “seasoned” with tiny fragments of another metal. It’s common practice for lots of batteries and semiconductors, and is a good way of getting some of the benefits of a new cathode metal without all the drawbacks or cost of building a whole cathode out of some niche material. In this case, the HBU scientists were looking to expand their salt battery’s capacity by upping its stability.

First, they tried scandium, which looked great on paper, though it didn’t actually improve stability all that much.⁴⁵ Next, they tried magnesium, but they didn’t hold out hope for it. You see, magnesium causes the exact kind of harmful redox reaction we’re trying to avoid. However, in a sodium-based setup, the team observed it suppressing this reaction instead. The researchers are still studying exactly why this happens, but it’s a promising step forward for a cheap sodium battery with prospects for better longevity and stability, great for those stationary storage applications.⁵

While we wait to see how this new advancement affects SIBs, they’re already making commercial headway. CATL, China’s (and probably the world’s) leading battery manufacturer told PV magazine that it “developed a basic industry chain for sodium ion batteries and established mass production.”⁶ European battery maker Northvolt unveiled their sodium NMC (Nickel Manganese Cobalt) battery back in November, and touted it as the company’s next-gen energy storage device.⁶ And back in January, Acculon Energy unveiled plans to scale their SIB production up to 2 GWh by mid-2024.⁸

There’s a lot of movement in the SIB sector. And hopefully it won’t be too long until a residential version hits the market, allowing homeowners with solar panels an affordable way to store their extra energy for later.

Thermal Energy Storage

As I go down my list of “what’s hot and what’s not” in the battery world, I would be remiss to ignore Thermal Energy Storage Device, AKA TES devices or thermal batteries. They’re unsurprisingly, a type of device that stores energy in the form of heat. And if you don’t convert the heat back into electricity, then thermal batteries tend to have incredible round-trip efficiency (RTE). You can get upwards of 90% of the energy you stored back out, without losing much to time, conversion, entropy, and so on. These are exciting because they pair really well with intermittent renewables like wind and solar. Collect all the solar and wind energy when conditions are good, squirrel it away for later.⁹¹⁰ Simple, right?

That simplicity extends to the medium that thermal batteries use to store their heat. There’s a lot to choose from, and for the most part, they aren’t cutting edge chemicals or space-age materials, but stuff you might find in your backyard. For instance, sand is looking to be one of the most promising types of thermal batteries because it has a low specific heat — meaning it’s easy to get hot, and in a large mass, it holds onto that heat quite well.¹¹ Because it’s just sand, there’s no chemical compounds with finite life spans or breakable moving parts. Sand is cheap and easy to find compared to the chemicals and precious metals of other batteries. For all those reasons and more, companies like Polar Night are using sand batteries to heat entire districts.¹² BatSand is going in the other direction, scaling down its sand battery for the residential market.¹³

And while TES batteries, are dirt simple, sand isn’t the only option. Rondo Energy has gone with special bricks as their medium. Thermal energy collected from renewable resources can heat the bricks up 1,500 C (2732 F), and the bricks can store that heat for days. Better yet, Rondo claims the battery can last for over 50 years.¹⁴ This battery works in a similar fashion to Brenmiller Energy’s bGen TES, which uses crushed up rocks. This battery achieves a lower temperature of just around 100 to 530 C (212 to 986 F), but that’s sufficient for some manufacturing requirements and building heating.¹⁵ Unless, of course, you prefer your home office kept at a toasty 500 C.

Thermal storage devices are efficient and cheap, but their biggest downside is just how big they are. The mechanics of storing heat means the bigger the better, so these things tend to be…cumbersome. Polar Night’s new sand battery measures 13 by 15 meters (or about 43 by 49 feet).¹⁶ Brenmiller’s bGen battery weighs 10 tons and is 12 meters long.¹⁵ I haven’t mentioned Vattenfall’s water-based TES in Berlin. Yes, you can make a TES with water. In fact, it’s not that different from your water heater. Vattenfall’s capacity is just a bit larger…as it’s a 45-meter (or 150 feet) tall behemoth holding 56 million liters.¹⁷ That’s the same amount of water as over 22 Olympic swimming pools.¹⁸ Heck, even BatSand’s tiniest residential-sized sand battery is 40 cubic meters.¹⁹

And while the size of thermal batteries certainly limits where and what we can use them for, it’s not that big a deal when it comes to the sort of application they’re best suited for like stationary storage. When storing enough energy to heat houses, buildings, or use the heat for manufacturing, having a large footprint is a small price to pay. Especially when sand, rocks, and water are so cheap.

Liquid Iron Flow

When it comes to energy storage, scalability is key, but storing energy isn’t as simple as storing more tangible objects. If you want more energy storage, sometimes you can’t simply build a bigger battery. Things aren’t that easy. Well, most of the time they aren’t.

Enter the flow battery. These batteries have an two tanks filled with different liquids. One tank acts as anode in the form of anolyte and the other acts as a cathode in the form of catholyte. Pumping them past each other, separated by a membrane, creates an electrochemical reaction and stores energy in chemical bonds. Quite simply, the bigger the tanks, the more energy you can store.²⁰

There’s now a ton of different flavors of flow battery like vanadium, zinc-bromine, several organic varieties, and the one I want to bring to your attention today: liquid iron flow (LIF).²¹
LIFs work just like other flow batteries, with two big tanks and separator. The twist is that both of the liquids at play here are just a liquid electrolyte dosed with slightly different iron(II) ions (hence the name). These materials are readily available, which makes these batteries cheap and easy to produce. Having the tanks filled with different kinds of iron atoms means that, unlike other flow batteries, if a little of tank A passes through the membrane and gets into tank B, it’s not going to cause permanent damage.²²

LIF batteries are nothing new, but earlier this year U.S. Department of Energy’s Pacific Northwest National Laboratory (PNNL) announced that it had made a breakthrough. Researchers added a chemical called nitrilotri-methylphosphonic acid (or NTMPA) to their liquid electrolytes, a commercially available substance usually used in water treatment plants to fight corrosion. Turns out, it’s also really good at storing charged iron ions at room temperature in a neutral pH.²²²³ Thanks to NTMPA, the research team reported that their initial design has an energy density of up to 9 watt-hours per liter (Wh/L). For reference, commercially available vanadium-flow batteries are already much denser, at around 25 Wh/L.²⁴ That’s alright though. For a “rough draft” on a lab bench, 9 Wh/L is a very promising start — especially for something made from easily available materials that can scale up so well.

LIFs do have some downsides to keep in mind. Like thermal batteries and souffles, they just don’t travel well. That’s on top of their relatively sluggish charge/decharge times and underwhelming energy density.²⁴ But these drawbacks aren’t really problems when it comes to applications like stationary energy storage. Here, scalability is key, and no battery scales up quite as easily as the flow battery.

In the past we’ve explored how other types of flow batteries are seeing success when paired with residential solar set-ups, so who knows? One day LIFs could be coming to a garage near you.

Solid State

We touched on Solid State Batteries (SSBs) early this year, and for good reason, they’re batteries that might be able to do it all. Having a solid core lets these batteries charge super fast, like a full EV battery in just 15 minutes kinda-fast. More importantly, it also fights dendrite growth, those metal spikes that grow as you use a battery that can kill it from the inside out.²⁵²⁶ Fewer dendrites means batteries survive more charging cycles than even lithium-ion tech, the current-gen king of the battery hill. At least in theory…^{27 28 29}

So, if SSBs aren’t yet living up to their intention just yet, why do I think they’re worth watching in 2024? They were one of those technologies that was always just another 5 or 10 years away from being reality because of how difficult they are to manufacture, let alone mass produce. Both QuantumScape and Solid Power have tackled manufacturing issues in their own ways.

QuantumScape has developed advanced processors that help deal with the notoriously tricky task of making the solid state separators for their anode-free battery design. And they claim they’ll soon be able to mass produce their batteries at gigawatt scale.³⁰³¹ Meanwhile, the core of Solid Power’s SSB is made from sulfides. These are less temperamental than traditional solid state materials, which should make it fairly easy for Solid Power to factory make them with commonplace roll-to-roll technology.³² Solid Power is building their factories right now, planning to make enough SSBs for 800,000 EVs by 2028.³³

So while these SSBs aren’t surpassing lithium just yet, they are super promising. Once solid state batteries are on the market, they could mature fast. That could see us work out the kinks and drop the costs so these batteries can finally live up to their super-dense promise. But only time will tell.

Silicon

Let’s close out with silicon batteries, the most powerful ones on this list. These are already seeing some commercial success and companies like Amprius, OneD and Sila Nanotechnologies are hoping to push it even further. Silicon is amazing at storing lithium ions. It takes just one silicon atom to store four lithium ions. That makes silicon anodes up to 24 times more efficient than graphite anode of your typical lithium-ion battery.³⁴ Being insanely energy-dense and relatively lightweight makes silicon batteries a theoretical great fit for the next generation of phones, wearables, and maybe even electric vehicles.³⁵

The big drawback to silicon is that it likes lithium a little too much. Reacting with the lithium ions can make the silicon anode dramatically balloon up and break the battery.³⁶ Companies like Amprius and OneD are tackling this issue by growing nanowires. These make excellent pathways for lithium ions to zoom across, making for a very energy dense battery. The space between the wires gives the swelling silicon some wiggle room.³⁷ Nanotech has also led to Sila’s solution: micrometer-size particles of nanostructured silicon and other materials that are protected by a porous scaffold. It’s another way of giving those ions freeways to cruise while making sure the silicon doesn’t swell out of control. From the outside, it looks and feels like a commonplace battery anode, which should allow them to use pre-existing battery manufacturing gear to mass produce their silicon batteries.³⁷

Of course, making nanotech at scale is very challenging, but these companies are pushing ahead and getting close to commercialization. Amprius has a working factory in Colorado, its product is on the market, and earlier this year, the company completed qualification for its SiMaxx mass production tool.³⁸ Amprius claims this will help its team increase production to 2 MWh of silicon batteries in 2025, which is 10 times what they expect to produce in 2024. Sila has two factories, one in California and one in Washington state, with a combined (expected) capacity of up to 150 GWh.³⁹

Any one of these companies could open the door to silicon batteries. And that could mean a revolution for just about every piece of tech that wants more power in a smaller package… which is basically everything.

That’s all just a taste of what’s to come. We’d be here forever if I were to list all the exciting new battery tech to watch in 2024 and beyond. It feels the battery sector is on the cusp of a transformative phase, one where lithium will still have its applications, but we’ll have a lot of other viable alternatives. Whether it’s stationary storage, EVs or anything else, I can’t wait to see what niches these batteries find and how they’ll make things green, more efficient, and better.