Today’s electronics all run on a 30-year-old compromise. The lithium-ion battery, commercialized by Sony in 1991, has been the quiet backbone of modern life. But anyone who has watched an EV lose 40% of its range in a Minnesota winter, or waited 45 minutes at a Supercharger on a road trip, or read about a scary battery fire, understands the deal we made: we accepted good enough because nothing better was ready.
That's about to change.
Enter solid-state batteries, the technology that replaces the flammable liquid electrolyte inside every lithium-ion cell with a thin, solid material: a ceramic, a sulfide glass, or a polymer film. No liquid means no fuel for a thermal runaway fire. But the implications go far beyond safety.
Why Solid-State, Why Now?
A conventional lithium-ion cell is, at its core, a sandwich: a cathode, an anode, and a liquid electrolyte in between that ferries lithium ions back and forth. The liquid works, but it imposes brutal constraints. It's flammable. It degrades. And it limits what the electrodes can be made of, because the most energy-dense anode material known—pure lithium metal—reacts violently with liquid electrolyte, sprouting metallic tendrils called dendrites that short-circuit the cell.
A solid electrolyte changes the equation. It can safely pair with a lithium-metal anode without the dendrite problem, unlocking roughly double the energy density (~400–500 Wh/kg versus ~250 Wh/kg today), charging from 10% to 80% in under 10 minutes, cycle life measured in decades rather than years, and dramatically improved safety even under puncture or crush.
For years, these benefits sounded too good to be true. Most solid-state milestones were confined to the lab. That’s no longer true.
In September 2025, Mercedes-Benz drove a modified EQS with solid-state cells 749 miles from Stuttgart to Malmö, Sweden on a single charge—and arrived with 85 miles still in the “tank.” Toyota has received Japanese government certification to begin solid-state production in 2026. Samsung SDI is targeting mass production in the second half of 2027.
The lab era is over; the factory era is beginning. These are the solid state battery stocks to watch, grouped by their role in the value chain.
Pure-Play Solid-State Developers
These are the companies whose entire reason for existence is to solve the solid-state problem. They carry the most risk and the most upside if they reach scale.
- QuantumScape (NASDAQ: QS) is the furthest along among the pure-plays. Its core innovation is a ceramic separator that enables a lithium-metal cell where the anode forms during charging rather than being pre-installed, a design that simplifies manufacturing and maximizes energy density. In 2025, QuantumScape achieved a 25x improvement in separator manufacturing speed, shipped its first cells to the Volkswagen Group (debuted in a Ducati motorcycle at the IAA show in Munich), and reported its first-ever customer billings ($12.8 million). In early 2026, it inaugurated its Eagle Line, an automated pilot line designed as the blueprint for gigawatt-scale licensing. The business model is capital-light: license the technology, sell the separators, let partners build the gigafactories.
- Solid Power (NASDAQ: SLDP) doesn't make complete battery cells, but it does make the solid electrolyte material inside them and license its cell designs to partners. The key advantage: its sulfide-based electrolyte is compatible with existing lithium-ion factory equipment, drastically lowering the cost of adoption for automakers. In late 2025, Solid Power signed a three-way partnership with Samsung SDI and BMW to build and validate a demonstration vehicle, and BMW has already tested its cells in an i7 prototype. Revenue was $21.7 million in 2025. A January 2026 stock-and-warrant offering raised $130 million, bringing total liquidity to ~$466 million, though the warrant structure carries meaningful dilution for existing shareholders.
Automaker-Led SSB Programs
These are the massive automakers whose solid-state R&D programs are among the most advanced in the world. While they don’t carry the same battery-tied upside as pure-plays, they benefit from clear distribution channels the moment solid-state is ready.
- Toyota (NYSE: TM) holds more solid-state battery patents than any company on earth, with over 1,000. In September 2024, it received production approval from Japan's METI for its all-solid-state battery program: pilot production in 2026, SSB-powered Lexus flagships by 2027–2028, targeting a 10-minute fast charge and up to 745 miles of range. Toyota has locked up its upstream supply chain through a joint development agreement with Idemitsu Kosan for mass-produced sulfide electrolytes and a cathode material partnership with Sumitomo Metal Mining. The risk: this timeline has been pushed back multiple times, originally targeting 2020 (!). But with a certified plan, a dedicated battery subsidiary, and the deepest IP portfolio in the space, Toyota remains the most credible large-scale program.
- Nissan (OTC: NSANY) has been running a pilot solid-state line at its Yokohama plant since early 2025, with prototype cells reportedly hitting mass-production performance targets. Its cost ambition is the boldest in the industry: $75/kWh by 2028, well below today's lithium-ion average of ~$115/kWh. This figure would bring SSB-powered EVs to cost parity with gasoline cars. The caveat: a planned megamerger with Honda collapsed in early 2025, and Nissan is now mid-turnaround under new CEO Ivan Espinosa. The SSB program is technically on track, but depends on a parent company under financial stress.
- Samsung SDI (KRX: 006400) operates Korea's first all-solid-state pilot line and holds over 1,000 SSB patent applications. It has branded the technology "SolidStack" and confirmed mass production for H2 2027, targeting 900 Wh/L or roughly 40% above current lithium-ion. Its go-to-market is distinct: rather than launching in cars, Samsung is targeting humanoid robots and industrial automation first, where safety and light weight justify premium pricing, then expanding into EVs through its partnerships with BMW and Solid Power.
SSB-Adjacent Technologies
Before a revolution can succeed, it must first prove it is better than the best of the old guard. The companies in this segment don't use a fully solid electrolyte, but they do push the boundaries of existing lithium-ion architecture with innovations like 100% silicon anodes or hybrid lithium-metal cells that deliver some of the same performance gains solid-state promises.
They are worth watching both as competitors and as potential acquirers of solid-state IP.
- Amprius Technologies (NYSE: AMPX) has built the highest-energy-density lithium-ion batteries commercially available today, using a proprietary silicon nanowire anode that stores roughly ten times more lithium per unit weight than conventional graphite. Its cells reach up to 450 Wh/kg, performance that overlaps with the low end of solid-state targets. Amprius has established a dominant position in defense and electric aviation, where low weight is paramount. Revenue tripled to $73 million in 2025, the company hit positive adjusted EBITDA in Q4, and 2026 guidance is $125–135 million. Amprius is the performance benchmark that solid-state developers are still trying to match on a production line.
- Enovix (NASDAQ: ENVX) tackled the problem with physics rather than chemistry. Instead of a new electrolyte, Enovix redesigned the architecture of the cell itself, precisely stacking 100% active silicon anodes, cathodes, and separators rather than rolling them into a conventional "jelly roll." The result: independently verified energy density of 935 Wh/L, among the highest of any commercially available batteries, in a form factor optimized for smartphones, smart eyewear, and defense. Revenue was $31.8 million in 2025 (up 38% year-over-year), with a high-volume fab in Penang, Malaysia preparing to scale for smartphone OEM launches in 2026.
- SES AI (NYSE: SES) was originally developing hybrid lithium-metal batteries for EVs with GM, Hyundai, and Honda but pivoted in 2025 after concluding that the EV battery cell business wasn't viable for a Western startup. SES now operates three business lines: energy storage systems (its largest revenue driver), NDAA-compliant lithium-metal drone cells manufactured in South Korea, and an AI-powered materials discovery platform called Molecular Universe. Revenue grew 10x to $21 million in 2025, with 2026 guidance of $30–35 million. SES is a cautionary tale about how hard the solid-state manufacturing problem really is, but its pivot to drones and AI materials may have found more immediate commercial footing.
Private Bellwethers
These are the companies you can't yet buy on a public exchange. Watch them as IPO candidates, acquisition targets, or leading indicators of where the technology is heading.
- Factorial Energy supplied the solid-state cells for the Mercedes-Benz EQS that drove 749 miles on a single charge. Its critical advantage: its cells are compatible with existing battery factory lines, so OEMs don't need to build new plants. Backed by Mercedes-Benz, Stellantis, and Hyundai with a Stellantis Dodge Charger Daytona demonstration fleet planned for 2026. Going public via SPAC merger expected mid-2026 (NASDAQ: FAC, ~$1.1 billion valuation).
- LiCAP Technologies (Sacramento, CA) is the dry-electrode specialist behind Nissan's solid-state push. Its process eliminates the expensive wet-coating step in conventional battery manufacturing, which is widely seen as the bottleneck SSBs must solve to compete on cost. Already operating a 300 MWh production line in California.
- Idemitsu Kosan (TYO: 5019, unlisted in the U.S.) is the upstream kingmaker, a Japanese petrochemical giant building a large-scale lithium sulfide production facility as the critical raw material for sulfide-based solid electrolytes, the chemistry favored by Toyota, Samsung SDI, and Solid Power. Think of it as the indium phosphide of solid-state batteries: a structural chokepoint that everyone needs and few can replicate.
Signals to Watch
For those tracking solid-state battery stocks, here are the near-term signals that matter:
- Toyota's 2026–2027 production ramp. If Toyota begins delivering solid-state cells on schedule, even in limited quantities, it will be the single most important validation event for the industry.
- Factorial's SPAC close and Stellantis fleet. If the Charger Daytona fleet hits the road in 2026, it will mark the first time American consumers can ride in a solid-state-powered vehicle.
- The cost curve. Solid-state cells today cost an estimated $400–800/kWh versus ~$115/kWh for lithium-ion. Nissan's $75/kWh target by 2028 is the number to watch. If anyone credibly hits it, the market explodes from luxury flagships to mainstream sedans.
- The sulfide supply chain. Lithium sulfide production is concentrated and capacity-constrained. Idemitsu's ramp will determine whether the industry scales or hits a materials bottleneck.
- Samsung SDI's robots-first strategy. By targeting robotics before EVs, Samsung could generate real revenue and real-world durability data while the automotive production lines are still scaling.
While the lithium-ion battery gave us the electric car, the solid-state battery might give us the electric car people actually want: one that charges like filling a gas tank, drives like it has no range limit, and doesn't make the evening news when it catches fire.