Energy
Sodium & Hydrogen Solid-State Batteries Challenge Lithium
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Moving Beyond Lithium-Ion
With the electrification of all forms of transportation, starting with cars, and soon also encompassing trucks, ships, and possibly even planes, battery storage has become the key technology of the decade.
It was initially dominated by lithium-ion technology, thanks to the experience in manufacturing it for small electronics, and the inherent electrical properties of lithium.
However, lithium-ion technology presents a few key issues that might limit its adoption:
- It is more expensive and rarer than other metals, potentially limiting its application to ultra-high-density batteries or high-end products.
- It tends to form metal dendrites that can cause catastrophic failures and battery fire.
- It operates poorly in freezing temperatures, making it unsuitable for cold climates and fixed storage in cold regions.
For all these reasons, scientists and battery manufacturers have been exploring alternative chemistries. One of these is using sodium, one of the components of ultra-abundant & cheap sea salt.
Sodium-ion batteries are soon reaching the mass production stage, with the company CATL (300750.SZ) leading the charge in that field.
“It’s not a matter of sodium versus lithium. We need both. When we think about tomorrow’s energy storage solutions, we should imagine the same giga factory can produce products based on both lithium and sodium chemistries,”
Shirley Meng– Professor in Molecular Engineering at the UChicago PME.
Still, both lithium-ion and sodium-ion batteries are expected to be a stepping stone toward a superior form of battery technology: solid-state batteries.
At first focused on lithium, solid-state technology is now expanding towards new directions. For example, we discussed previously the possibility of an anode-free solid-state battery based on sodium.
A new study revealed that a metastable form of sodium solid electrolyte could be used to create solid-state sodium batteries that are not only more energy dense but also maintain performance even at subzero temperatures.
This work was performed by scientists at the University of California, the University of Chicago, and National Taiwan University of Science and Technology, and was published in the journal Joule1 under the title “Metastable sodium closo-hydridoborates for all-solid-state batteries with thick cathodes”.
Challenges of Solid-State Electrolytes
In a “normal” battery, the cathode and anode are separated by a liquid electrolyte. This electrolyte is very useful, but also very heavy, and the main cause of fire in faulty batteries.
This is why replacing it with a layer of solid material makes the battery not only a lot denser, but also safer. However, keeping this solid electrolyte stable and not swelling when charging or discharging the battery (causing cracks) has been an issue.
Sodium solid electrolytes have an extra problem, as they show limited room-temperature ionic conductivity.
An alternative could be using material like sodium hydridoborate, known to have a very high ionic conductivity. But for that, its metastable form needs to be maintained in a battery at scale.
“This metastable structure of sodium hydridoborate has a very high ionic conductivity, at least one order of magnitude higher than the one reported in the literature, and three to four orders of magnitude higher than the precursor itself.”
Shirley Meng– Professor in Molecular Engineering at the UChicago PME.
Stabilizing Sodium Solid-State Electrolytes
When producing a battery with sodium hydridoborate, the material tends to move toward a stable structure when cooling, separating NaBH4 from Na2B12H12 molecules.
A metastable form exists at high temperature, mixing the 2 crystals, allowing for much quicker movement of sodium in the battery, leading to stronger electrical capacity.
Source: Joule
When cooling quickly, the material in a metastable form, the crystal keeps its structure, instead of falling back into a stable form. This sort of quick cooling, also called quenching, is a key method used in manufacturing, notably in metallurgy for steel and other metals.
Source: Joule
Known Technique For Scalability
It was already known that to stabilize a chemical structure, quenching (rapid cooling) is often a useful method. However, this had never been demonstrated in a solid-state electrolyte until now.
The fact that this is a commonly accepted practice could greatly help in making this technique scalable and adopted by battery manufacturers.
“Since this technique is established, we are better able to scale up in the future.
If you are proposing something new or if there’s a need to change or establish processes, then industry will be more reluctant to accept it.”
Sam Oh – A*STAR Institute of Materials Research and Engineering in Singapore.
Thick Electrode & Cold Temperatures
Most solid-state designs try to engineer an ultra-thin cathode to maximize the contact surface and limit the amount of “dead” material that does not store energy.
The quenching solves this issue by creating permanent pores where the sodium ion can circulate.
“Pairing that metastable phase with a O3-type cathode that has been coated with a chloride-based solid electrolyte can create thick, high-areal-loading cathodes that puts this new design beyond previous sodium batteries.”
Sam Oh – A*STAR Institute of Materials Research and Engineering in Singapore.
This creates an interesting design potential, as making the electrode thicker should, in this specific case, improve the battery, instead of making it worse.
“The thicker the cathode is, the theoretical energy density of the battery – the amount of energy being held within a specific area – improves,”
Sam Oh – A*STAR Institute of Materials Research and Engineering in Singapore.
When testing the cathode, the researchers found that performance held at room temperature and even below freezing—a notable advantage for cold-climate operation compared with conventional liquid-electrolyte Li-ion—though broader, system-level superiority to commercial Li-ion has not yet been demonstrated.
Hydrogen As A Charge Carrier
When discussing hydrogen in relation to transportation and green energy, we generally refer to dihydrogen (H2) and its combustion or oxidation in dedicated engines or fuel cells.
But hydrogen could have potential as a key component of batteries in the future as well, replacing lithium or sodium. In that case, hydride (H-) is used instead.
As hydrogen is the Universe’s most abundant element, this could make it especially useful for a world aiming to be entirely electrified and running on green energy and batteries.
Chinese researchers at the University of Chinese Academy of Sciences, University of Science and Technology of China (USTC), Jilin University, and the People’s Republic of China State Key Laboratory of Catalysis have revealed in the prestigious scientific review Nature2 the concept of a solid-state hydride ion battery, under the title “A room temperature rechargeable all-solid-state hydride ion battery”.
Hydride Ions
Batteries use a negative charge carrier to transport electrons between the anode and cathode. In theory, hydride ions (H−) are more energetic, polarizable, and reactive than cations like lithium or sodium.
Hydrogen is also the smallest atom, making it especially light, a key point for batteries used in transportation.
However, despite these well-known advantages, hydride ions have not been used in batteries so far, as no electrolyte has been able to provide the combination of rapid ion movement, thermal stability, and electrode compatibility that such systems require.
Combining Conductivity To Stability
The researchers synthesized a novel core–shell composite hydride, 3CeH3@BaH2, where a thin BaH2 shell encapsulates CeH3. This structure leverages the high hydride ion conductivity of CeH3 and the stability of BaH2.
Using this shell composite as a building block, the researchers created a CeH2|3CeH3@BaH2|NaAlH4 all-solid-state hydride ion prototype. NaAlH4, a classical hydrogen storage material, was used as the cathode active component.
Removing Dendrite Forever?
Besides high energy capacity, hydride ions have another major advantage: contrary to metallic cations, they cannot assemble with each other to form dendrites, the root cause of most battery failure after too many charge-discharge cycles, causing short-circuits and fires.
So it could be the way for safe, efficient, and sustainable energy storage.
However, this technology is a lot less mature than lithium batteries or even sodium batteries, with progress needed in the durability of this design.
For now, the researchers managed to create a high energy density of 984 mAh/g at room temperature. But the battery capacity declined to 402 mAh/g after just 20 cycles.
The Future of Solid-State Batteries
For the near-term, batteries using lithium-ion technology are likely to stay a basis of green energy and EVs.
However, in the medium term, solid-state batteries or sodium (and solid-state sodium) could displace lithium-ion dominance, especially if they manage to offer high enough energy density at a lower price.
Solid-state batteries’ quick charging could also be an argument for drivers reluctant to switch to EVs or commercial applications.
Durability and tolerance for cold temperatures will also be a factor in the equation, with potentially a wide array of parallel battery chemistries co-existing throughout the 2030s, with some specialized batteries for EVs in cold climates.
You can read more about these topics in our following articles:
Swipe to scroll →
| Battery Type | Energy Density | Cycle Life | Cost | Maturity |
|---|---|---|---|---|
| Lithium-Ion | 250–300 Wh/kg | 1,000+ cycles | High | Commercial |
| Sodium-Ion | 160–200 Wh/kg | 1,000+ cycles | Lower | Scaling (CATL) |
| Solid-State (Lithium) | 350–500 Wh/kg | >2,000 cycles (target) | High (R&D) | Pilot (2026–27) |
| Hydride Ion | 984 mAh/g (prototype) | 20 cycles (current) | Unknown | Early Research |
Solid-State Battery Company
QuantumScape
(QS )
Since its foundation in 2010, Californian QuantumScape has been a prominent startup in the solid-state battery space, remarkable by its move into the field early, and its independence from larger battery manufacturers also pursuing solid-state technology, like CATL (300750.SZ), Samsung, or LG Energy Solution (373220.KS).
Source: QuantumScape
One unique feature of QuantumScape batteries, which at the time of its reveal was considered revolutionary, is that it uses an anode-free design.
It allows for ~15-minute fast charge (10-80% at 45 ºC) and the separator is nonflammable and noncombustible.
Source: QuantumScape
This also puts QuantumScape batteries in a league of their own when it comes to energy density and charging speed, massively outperforming leaders like Tesla (both its own design and CATL-made ones).
Source: QuantumScape
However, these remarkable performances have been regularly hindered by a struggle to ramp up production. It also forced the company to burn through its cash pile, leading to previous investors’ dilution and a decline in share prices.
This seems to be changing since the 2024 agreement with PowerCo, the Volkswagen Group battery division, for a licensing deal for the design and mass production of QuantumScape batteries by PowerCo.
Under the non-exclusive licensing deal, PowerCo can manufacture up to 40 gigawatt-hours per year of electric vehicle batteries, with the option to expand to 80 GWh a year.
The sudden scaling-up of QuantumScape production is linked to Cobra, the company’s next-generation solid-state battery separator equipment, a breakthrough in ceramics manufacturing.
Overall, Cobra should be integrated into production in 2025, and the first finished EV using QuantumScape batteries should be produced in 2026.
Source: QuantumScape
This could be a turning point for the company, moving 16 years after founding from a promising startup with interesting IP to generating growing revenues from a partnership with one of the largest automakers in the world.
The relation with PowerCo is getting closer in 2025, with solid-state batteries used in a Ducati motorbike, and as PowerCo will be providing up to $131 million in new payments over the next two years upon the joint scale-up team achieving certain milestones.
“This expanded agreement is a clear signal of the growing strategic, technical, and financial alignment between the two companies.
It reflects our shared confidence in QSE-5 as a game-changing platform for the battery industry.”
In the meantime, investors should still expect some volatility in the stock price, but with a light at the end of the product development tunnel.
(You can also check other battery companies in the US and abroad in our article
“Top 10 Battery Stocks To Invest In”).
Study Referenced
1. Jin An Sam Oh, et al. Metastable sodium closo-hydridoborates for all-solid-state batteries with thick cathodes. Joule. 102130. September 16, 2025. https://www.cell.com/joule/abstract/S2542-4351(25)00311-3
2. Jirong Cui, et al. A room temperature rechargeable all-solid-state hydride ion battery. Nature. 17 September 2025. https://doi.org/10.1038/s41586-025-09561-3
