Lithium-ion batteries have become the global standard. Today, it is the most popular and widely used type of battery, with its market size estimated to be valued at about $65 billion in 2023.
But, of course, they are not without drawbacks, including temperature sensitivity, safety concerns, and limited lifespan.
To make Li-ion batteries safer and more powerful, liquid electrolytes are being replaced with solid ones to create solid-state batteries, whose market is projected to grow at a CAGR of 41.6% between 2024 and 2032.
A Shift to Solid-State Batteries (SSBs)
In a battery, the electrolyte is the material that makes it possible for ions to move through the device to generate power.
So, a battery that has a solid electrolyte is a solid-state battery, which provides higher energy density, faster charging, temperature resilience, longer timespan, and enhanced safety.
Despite their promise, SSBs also face several challenges, including complex manufacturing and potential safety concerns related to dendrite formation. Also, they can experience interfacial delamination, limiting their performance and lifespan. Together, these limitations are hindering the widespread adoption of SSBs.
To overcome these challenges, researchers and companies around the world are actively working on advancing the tech.
For instance, Samsung SDI is targeting an energy density of 900 Wh/L through its proprietary solid electrolyte and anode-less technologies, 40% higher than its current batteries.
Chinese giants CATL and BYD are also making significant strides in SSB tech, with the former working on a hybrid “condensed state battery” and the latter researching oxide- and sulfide-based solid electrolytes, both targeting an energy density of 500 Wh/kg.
In the EU, Volkswagen has partnered with QuantumScape (QS +5.89%). Its battery unit, PowerCo, has also secured a licensing deal to mass-produce solid-state cells with an initial capacity of 40 GWh annually, 30% more range, and ultra-fast charging.
Nissan is planning to begin mass production of its first solid-state cells before the decade is over, while LG is targeting 2030 for commercialization. Solid Power, meanwhile, has partnered with Ford (F +0.47%), BMW, and SK Innovation to accelerate the commercialization of all-solid-state battery technology with a focus on sulfide-based solid electrolytes for EVs.
Earlier this month, German multinational automotive company Mercedes-Benz Group AG (formerly Daimler) unveiled the first car powered by a lithium-metal SSB on the road. The prototype SSB was integrated into an EQS late last year.
The SSB in an EQS-based vehicle can increase the driving range by 25%, noted the company.
So, while in progress, the commercialization of SSBs is still several years away. In the meantime, a team of researchers from the University of Texas at Dallas has discovered a way to boost the performance of solid-state batteries.
Enhancing Ionic Conductivity in SSBs
Published in ACS Energy Letters, the latest study details the discovery of an enhanced ionic conductivity1 upon mixing a solid electrolyte with another solid.
This increased ionic conductivity is caused by the formation of a space charge layer at the interface, providing a new strategy for developing fast ionic conductors for SSBs. The ‘space charge layer’, as a result of the mixing of small particles between two solid electrolytes, is an accumulation of electric charge at the interface between the two materials.
What happens is that when the solid electrolyte materials, which are separate, make physical contact, a layer is formed at their boundary. At the boundary, charged particles accumulate because of differences in the chemical potential of each material.
The layer then helps create pathways that make it easier for these charged particles or ions to move across the interface. According to the study’s co-corresponding author, Dr. Laisuo Su, who is an assistant professor of materials science and engineering in the Erik Jonsson School of Engineering and Computer Science:
“Imagine mixing two ingredients in a recipe and unexpectedly getting a result that is better than either ingredient alone.”
He added:
“This effect boosted the movement of ions beyond what either material could achieve by itself,” he added.
Dr. Su’s research is focused on developing revolutionary materials for renewable energy devices in the rechargeable battery space. Besides having a special interest in electrolytes, both solid and liquid, as well as the electrolyte-electrode interface, where crucial reactions take place, he is working on building advanced tools to monitor chemical and electrochemical reactions occurring in renewable energy equipment.
“This discovery suggests a new way to design better solid electrolytes by carefully choosing materials that interact in a way that enhances ionic movement, potentially leading to better-performing solid-state batteries.”
– Dr. Su
As part of UTD’s Batteries and Energy to Advance Commercialization and National Security (BEACONS) initiative, which received a $30 million funding from the Department of Defense upon launch in 2023, the project aims to develop and commercialize new battery tech and manufacturing processes, improve domestic availability of critical raw materials, and train high-quality workers for industry.
According to the study’s co-corresponding author, Dr. Kyeongjae Cho & who is also a professor of materials science and engineering and director of BEACONS:
“Solid-state battery technology is part of our next-gen battery chemistries research at the BEACONS center, and it is expected to enable advanced battery systems to improve the performance of drones for defense applications.”
Lithium-ion batteries currently used in consumer products primarily include liquid electrolytes, which are inflammable and hence present safety issues.
With conventional Li-ion batteries reaching their theoretical limit of just how much energy they can store, SSBs, according to Su, showcase promise for generating and storing more than twice as much power as batteries with liquid electrolytes. And because they aren’t flammable, they are also safer.
Moving ions through solid materials, however, is difficult, which creates challenges in solid-state battery development.
So, the researchers studied the performance of two promising solid-state electrolyte (SSE) compounds. This includes lithium zirconium chloride (Li2ZrCl6) and lithium yttrium chloride (Li3YCl6).
The researchers then proposed a theory as to why mixing these boosted ionic activities. “The interface formed unique channels for ion transport,” Su said.
Moving forward, the researchers will continue to study how the composition as well as the structure of the interface results in greater ionic conductivity.
Tackling the Dendrite Problem in SSBs
The need for batteries with higher energy densities has led to another team of researchers working on the critical dendrite problem. Originally, it was thought that dendrites couldn’t penetrate the solid electrolyte. But much like other battery architectures, they are also an issue for all-solid-state batteries.
A team of engineers and materials scientists from several institutions in China has discovered2 that metal fatigue at the anode is one of the big reasons why SSBs fail over time. It also contributes to the degradation of the interface and the growth of dendrites.
The group used scanning electron microscopy and phase-field simulations to study dendrite growth in Lithium SSBs.
What they found was that during charging and recharging, the constant swelling and contraction of lithium caused metal fatigue to occur in the anode, which promoted dendrite growth. More specifically, the constant expansion and contraction were found to be leading to the development of microvoids and cracks at the anode, which led to dendrite growth and degradation, even at low densities.
As to what a dendrite is, it is a tree-like structure that forms due to chemical reactions on the anode’s surface.
Anodes in a battery go through lithium plating and stripping processes during charge and discharge cycles. In this reversible process, lithium ions are deposited on the anode’s (plating) surface and removed (stripping) from it during the normal cycling (charging & discharging) operations of the battery.
A non-uniform deposition of li-ions on the anode’s surface, however, tends to produce sites that attract more li-ions, which leads to a chain of lithium ions growing longer. The tree-like structure then penetrates through the battery, breaking down the battery structure and causing it to short circuit.
In SSBs, there’s a large contact area between lithium metal and the solid electrolyte. And if any voids appear in the solid electrolyte, lithium metal quickly fills them, causing serious dendrite formation and deep crack propagation through the electrolyte.
So, Haegyeom Kim, a materials staff scientist at Lawrence Berkeley National Laboratory in California, published3 a solution to this problem.
Their study details using a dual buffer layer of tin-carbon on the current collector to prevent the formation of dendrites in lithium, anode-free all-solid-state batteries (ASSBs). In this SSB architecture, an anode isn’t constructed beforehand, but rather it is formed during the first charge cycle on the current collector by the li-ions from the cathode to reduce complexity, weight, and cost.
A previous paper from researchers at Samsung showed the possibility of using silver and carbon layers as a buffer layer in lithium batteries, possessing a very stable and uniform lithium plating and stripping cycle.
Upon studying why this was effective, Kim’s team found that silver is very lithophilic, and the li-ions align uniformly on top of its layer, even when there are high concentrations of lithium, making the lithium plating very homogenous as long as the silver deposition was uniform.
Understanding the carbon’s role here, however, formed the basis for the new work, where the team selected tin, which works better than the costly silver.
To find out carbon’s role, the team designed multiple tests and used four different battery half-cells. One with a tin buffer layer, one without a buffer layer, one with tin on top of the carbon buffer layer, and one with carbon on top of the tin buffer layer.
The layers were deposited onto a stainless-steel current collector, and the buffer layer with the carbon on top of the tin showed the best performance.
“We realized that the tin acts as a lithophilic layer like silver, so the tin positioning is important, as that’s where the plating happens.”
– Kim
The carbon layer was found to be lithophobic, which means li-ions struggled to move through this layer, rather wanting to go the opposite way. Placing it on the tin prevented the migration of lithium from the newly developed plating layer on the tin and stopped the penetration of dendrite into the electrolyte.
According to Kim:
“It’s not just about the intrinsic properties of a single material. How we combine them is so important, as that can significantly change the properties of the barrier layer.”
The team is now working on new buffer layers with better performance, testing over longer cycles, and moving on to more practical systems.
Removing the Voids to Boost Longevity
Yet another breakthrough in bringing SSBs another step closer to real-world applications was made by understanding just why adding small amounts of metals like magnesium to the anode improves battery performance.
While this is done frequently, it wasn’t known just why that was so until now.
For this, researchers from the University of Houston took a look inside all that’s happening in SSBs using operando scanning electron microscopy to understand why they break down and what could be done to slow that process.
“This research solves a long-standing mystery about why solid-state batteries sometimes fail,” said corresponding author Yan Yao, the Hugh Roy and Lillie Cranz Cullen Distinguished Professor of Electrical and Computer Engineering and principal investigator at the Texas Center for Superconductivity.
Their discovery4, according to Yao, allows SSBs to function under lower pressure. This can potentially reduce the requirement for bulky external casing and enhance overall safety.
What has been learned is that over time, tiny voids form within the battery to form a large gap, which causes the battery to fail. Conducting several trials revealed that just adding a small quantity of elements like magnesium (Mg) can close these spaces and help the battery continue to function.
“With just a small tweak to the battery’s chemistry, we can dramatically improve its performance, especially under practical conditions like low pressure.”
– First author Lihong Zhao, an assistant professor of electrical and computer engineering at UH
SSBs need high external stack pressure to stay intact while operating, but as Zhao noted, “by carefully adjusting the battery’s chemistry, we can significantly lower the pressure needed to keep it stable.”
Researchers from the University of Missouri, meanwhile, used four-dimensional scanning transmission electron microscopy (4D STEM) to assess the battery’s atomic structure.
What they found was that when the solid electrolyte touches the cathode, it reacts and forms an interphase layer with a 100 nm thickness, which blocks the li-ions and electrons from moving easily, in turn, limiting battery performance.
The research team now plans to test whether thin-film materials formed by a vapor-phase deposition process (oMLD) can provide a protective coating “thin enough to prevent reactions” in between the solid electrolyte and cathode materials, “but not so thick that they block lithium-ion flow.”
Using AI to Aid SSB Research & Development
With artificial intelligence transforming industries, it makes sense that researchers are also taking its help to solve the problem of SSB research and development, which are resource-intensive and time-consuming.
The complex chemical environment of SSB actually makes performance prediction difficult and delays large-scale industrialization.
In a study5 from last week, engineers from Soochow University and Nanjing University, China, pointed out AI’s potential to enable efficient material screening and performance prediction. The latest progress in using machine learning (ML) algorithms, it noted, can be used to mine extensive material databases and accelerate the discovery of high-performance materials suitable for SSBs.
The rapid development of AI technology, as per the study, provides new ideas for addressing major challenges with SSBs, which are the anode interface, the cathode interface, the synthesis and discovery of electrolytes, and battery manufacturing.
Researchers from Skoltech and the AIRI Institute also took advantage of neural networks and found them capable of identifying promising materials for the solid electrolyte as well as its protective coatings.
“We demonstrated that graph neural networks can identify new solid-state battery materials with high ionic mobility and do it orders of magnitude faster than traditional quantum chemistry methods,” potentially speeding up the development of new battery materials, said lead author, Artem Dembitskiy.
Using the machine learning-accelerated approach, the researchers identified compounds Li3AlF6 and Li2ZnCl4 as promising coating materials for the superionic lithium conductor Li10GeP2S12.
Investing in SSB technology
When it comes to investing in a company actively advancing solid-state battery technology, Toyota (TM -1.34%) offers solid potential.
The Japan-based automaker has partnered with Panasonic to form a joint venture called Prime Planet Energy & Solutions, focusing on sulfide-based solid electrolytes. The company plans to begin production next year, with mass production not expected till 2030, targeting a 1,000 km range, 10-minute fast charging, and an annual capacity goal of 9 GWh.
It has also partnered with Idemitsu Kosan to mass-produce sulfide-based electrolytes by 2027–2028.
Toyota Motor Corp (TM -1.34%)
Toyota’s tryst with solid-state batteries began close to two decades ago with the establishment of a Battery Research Division, whose purpose is to develop next-generation batteries for hybrid and electric vehicles.
When it comes to the market performance of Toyota Motors, it has been pretty strong, with its shares currently trading at $183.60. While down 4.87% YTD, they are up over 17% since their April low. Just last year, in March, the company’s stock price had surpassed $255 to hit a new peak.
Toyota Motor Corporation (TM -1.34%)
With that, the $292.4 billion market cap, Toyota’s EPS (TTM) is 24.01, and the P/E (TTM) is 7.71. It even offers an attractive dividend yield of 3.27%.
The company’s financial results for Q1 2025 showed its net revenue increased by 6.5% to $314 billion, while operating income decreased by over 15% to $31.3 billion. During this period, the company sold a total of about 9,362,000 units. Despite the sales decreasing by 81,000 units in the quarter, Toyota was still the best-selling brand.
This comes after Toyota sold 10.8 million vehicles in 2024 to become the world’s top-selling automaker for the fifth straight year.
Latest Toyota Motor Corp. (TM) Stock News and Developments
Click here for a list of the five best solid-state battery stocks.
Conclusion: The Future of Solid-State Batteries
Solid-state batteries promise a lot of benefits over the widely used lithium batteries. While they offer better safety, energy density, and longevity, challenges like interfacial delamination and dendrite formation still hinder their mass adoption.
Here, the latest discovery that mixing certain solid electrolytes creates a “space charge layer,” which improves ion mobility, represents a promising new direction. Through such breakthroughs, along with constant experimentation by companies, SSB can finally be made viable for real-world use in mobile devices and EVs.
Click here to learn about a breakthrough that made solid-state batteries one step closer to reality.
Studies Referenced:
1. Wang, B., Limon, M. S. R., Zhou, Y., Cho, K., Ahmad, Z., & Su, L. (2025). 1 + 1 > 2 Effect induced by space charge in solid electrolytes. ACS Energy Letters, 10(3), 1255–1257. https://doi.org/10.1021/acsenergylett.4c03398
2. Wang, T., Chen, B., Liu, Y., Song, Z., Wang, Z., Chen, Y., Yu, Q., Wen, J., Dai, Y., Kang, Q., Pei, F., Xu, R., Luo, W., & Huang, Y. (2025). Fatigue of Li metal anode in solid-state batteries. Science, 388(6744), 311–316. https://doi.org/10.1126/science.adq6807
3. Avvaru, V. S., Ogunfunmi, T., Jeong, S., Diallo, M. S., Watt, J., Scott, M. C., & Kim, H. (2025). Tin–carbon dual buffer layer to suppress lithium dendrite growth in all-solid-state batteries. ACS Nano, 19(18), 17347–17356. https://doi.org/10.1021/acsnano.4c16271
4. Zhao, L., Feng, M., Wu, C. et al. Imaging the evolution of lithium-solid electrolyte interface using operando scanning electron microscopy. Nat Commun 16, 4283 (2025). https://doi.org/10.1038/s41467-025-59567-8
5. Wang, S., Liu, J., Song, X. et al. Artificial Intelligence Empowers Solid-State Batteries for Material Screening and Performance Evaluation. Nano-Micro Lett. 17, 287 (2025). https://doi.org/10.1007/s40820-025-01797-y