Electric vehicle (EV) battery design keeps colliding with the same problem. Higher energy density can extend range, but it can also raise the risks tied to safety and thermal management. Solid-state batteries come up often as a way forward, though ProLogium cautions that swapping a liquid electrolyte for a solid-state one does not settle the question on its own.
An energy innovation company, ProLogium’s fourth-generation battery technology is built around a superfluidized all-inorganic solid-state electrolyte. The design aims to pair the conductivity and interface adaptability that high performance demands with cell-level safety features meant to address thermal runaway.
“The market does not necessarily need solid-state batteries. It needs safe, high-energy-density, high-performance batteries,” shares Vincent Yang, ProLogium’s founder, CEO, and CTO. For Yang, the central limitation of today’s EVs sits in the conflict between energy density and safety.
ProLogium’s solid-state battery cells use a superfluidized all-inorganic electrolyte as part of a cell-level approach to reducing thermal runaway risk.
That conflict is where Gen 4 comes in. Its electrolyte platform is built to support high-energy-density materials without giving up safety. The same design also targets ultra-fast charging and low-temperature operation while simplifying pack architecture.
A material-level approach to thermal runaway prevention
Thermal runaway prevention in EV batteries typically gets handled across several layers, from chemistry and cell design through module design, pack structure, and thermal management. The company starts at the material and component level.
“ProLogium installs a triple safety mechanism at material and component level to effectively prevent thermal runaway at cell level,” Yang says.
The first element is the electrolyte itself. The superfluidized all-inorganic solid-state electrolyte is synthesized from inorganic materials and is built to stay non-flammable at temperatures between 750° and 900° C.
The second is a ceramic separator, designed to tolerate higher temperatures than conventional polypropylene or polyethylene separators. Separator failure inside a cell can open the door to an internal short circuit leading to thermal chain reaction, and the ceramic version is meant to hold off internal shorts and thermal propagation under high heat. It also keeps its structure well above 1000° C and conducts heat about three times better than conventional separators.
The third is the active safety mechanism, or ASM, embedded in the electrolyte. Here Yang gets specific. “Electrolyte decomposes in ASM material under approximately 125° C and stabilizes the source of thermal risk, the cathode and anode, turning them into different compounds, preventing thermal runaway risk at its root,” he says.
In practical terms, the goal is not to contain a thermal event but to eliminate the conditions for runaway .
Fast charging as a transport and polarization challenge
Ultra-fast charging sets a different problem. “Fast charging without excessive heat generation is a transport and polarization challenge,” Yang says. “To enable 5 to 80% charging within minutes, lithium ions should move rapidly through the cell while minimizing all forms of resistance and polarization.”
Three electrolyte properties are central to fast charging. The first is high ionic conductivity, rated at 57 mS/cm for the fourth-generation material. The higher that figure, the faster lithium ions can move through the electrolyte, which matters when a cell is taking on heavy charging current.
Interface behavior carries similar weight. Poor contact between the electrolyte and electrode surfaces raises interfacial impedance in solid-state cells, adding resistance and localized heat. The electrolyte is designed with non-Newtonian fluid behavior so that contact stays more uniform across the interface, lowering impedance along with side reactions and polarization.
The third property is a high lithium-ion transference number, meaning most of the current is carried by lithium ions rather than other species. That keeps concentration polarization down and the lithium distribution more even while the cell charges quickly.
The net effect is lower polarization and resistance, allowing the cell to pull high charging current while the heat generation stays in check. The cell also holds beyond 1,200 cycles within a 10 to 80% charging window.
Managing heat in larger-format cells
Higher energy density and faster charging make temperature uniformity harder to maintain across larger-format cells. Cell geometry can help address that challenge by shaping the path heat takes through the cell, especially when the design increases surface area while reducing thickness.
“Heat dissipation is more efficient along the planar direction of a cell than through its thickness,” Yang says. “To leverage this advantage, ProLogium developed the LLCB, which increases cell footprint while reducing thickness.”
The company reports that at the same capacity, the LLCB, its Large Lithium Ceramic Battery, runs roughly 25% cooler and shows up to 77% less temperature variation than conventional cell designs.
The swappable battery pack, developed with CEA, the French public research organization, uses large-format cells measuring 206 by 560 by 3.46 mm, with 24 vertically stacked cells per module and eight modules per pack. That layout is meant to lift energy density while making service simpler, since a single module could be swapped instead of the whole pack.
Yang notes the architecture can support fast charging that adds up to 360 km of driving range in 6.4 minutes, depending on system design and application.
Reducing pack-level thermal hardware also opens up packaging. A smaller, thinner pack frees cabin space and gives automakers more room inside existing chassis limits. “Whether for premium vehicles or compact cars, manufacturers no longer need to compromise vehicle design due to battery size constraints,” he adds.
The same pack is aimed at uses spanning executive vehicles to mass-market EVs, with the goal of an ownership experience closer to combustion cars. It can also sit in designated safety zones, the areas automakers flag through crash data as least likely to take a hit in a collision.
For all the attention solid-state draws, Yang ties adoption to whether the technology can meet real market needs at scale.
“Next-generation batteries will inevitably enter the market through premium vehicles first, before expanding into executive and mass-market segments as production scales,” he says.
That path tracks how new battery chemistries usually arrive. Premium platforms can carry higher early costs and place more value on range, charging speed, and safety, while wider adoption waits on manufacturability, lower cost, and validation across everyday driving.
Voltage and temperature response during thermal abuse testing, showing how a cell-level safety mechanism responds as temperature rises.
Yang is also careful not to overstate what the broader category delivers. “Adopting a solid-state electrolyte alone does not guarantee safety,” he notes. “Studies have shown that solid-state electrolyte can still undergo thermal runaway and may even exhibit more aggressive reactions with high-energy-density electrode materials.”
That framing casts the technology less as a solid-state battery and more as a system-level answer to the safety, cost, and manufacturing barriers that have slowed the category. The closing argument rests on the ASM work at the cell level.
“By leveraging our proprietary ASM technology to prevent thermal runaway at the cell level, Gen 4 enables the use of high-energy-density materials without compromising safety,” Yang says.
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