Solid-state battery stocks could rise sharply if the technology reaches dependable, cost-effective production and wins substantial automaker demand. But development milestones and partnerships are not proof of mass production—or evidence that a stock is undervalued. Recent disclosures from QuantumScape and Solid Power show active development, while leaving major manufacturing, commercial and valuation questions open.
What makes a battery “solid-state”?
In a conventional lithium-ion cell, a liquid electrolyte helps lithium ions move between the electrodes. Solid-state designs use a solid electrolyte instead. The label covers multiple architectures, materials and manufacturing approaches; companies using it are not necessarily developing interchangeable products.
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QuantumScape: solid-state lithium-metal technology
QuantumScape describes its focus as solid-state lithium-metal battery technology. Its June 18, 2026 announcement concerned a multi-year joint research agreement with Honda R&D following a technology evaluation. The disclosed scope includes work on the battery platform and related manufacturing processes. It is evidence of a partner’s technical engagement, not a mass-production order or a guaranteed vehicle launch.
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1Fix the driver behind crashes, sound loss and screen glitches2Clear out junk files and repair common Windows errors3Scan for outdated or missing drivers - takes under a minuteSolid Power: sulfide electrolyte and licensing
Solid Power develops sulfide solid electrolyte and cells. Its 2025 Form 10-K describes a business model centered on supplying electrolyte and licensing cell designs and manufacturing processes, rather than becoming the sole commercial cell manufacturer. That distinction matters: its commercial prospects depend partly on partners’ ability to develop, qualify and manufacture cells using its materials or processes.
#1 Best Overall
- Semi-Solid-State Battery for Safer Travel Power: Semi-solid-state battery design helps deliver safer, more stable charging in hot, cold, and everyday travel conditions. This portable charger power bank is built for road trips, flights, camping, commuting, and daily carry when reliable backup power matters.
- 10,000mAh Power Bank, Slim Enough for Every Day: Get 10,000mAh power in an ultra-slim 0.57-inch body that weighs only 6.9 oz. This small portable charger slips easily into a pocket, purse, backpack, or carry-on, giving you dependable power without the bulky brick feel.
- 15W Wireless + 30W USB-C Fast Charging: Snap on for up to 15W magnetic wireless charging, or plug in for up to 30W USB-C fast charging when you need power fast. A flexible magnetic portable charger and power bank for iPhone 16, 15, 14, 13, and 12 series.
- Built for Flights, Hotels, Road Trips, and Long Days Out: TSA-friendly capacity makes this battery pack charger portable for air travel, vacations, theme parks, work trips, and power outages. Pass-through charging lets you charge your phone and power bank together overnight with one USB-C cable.
- Smart Display, Low-Current Mode & TORRASCare Support: The digital display shows remaining battery at a glance before you head out. Low-current mode supports earbuds, AirPods, and other small devices, while 18-month TORRASCare support gives you added confidence for daily use and travel.
Why the technology could create a stock catalyst
The investment thesis is that a successful solid-state cell could offer automakers a useful combination of performance, safety, charging and cost characteristics. If a company can demonstrate those benefits in customer-qualified cells and manufacture them consistently at competitive cost, automaker adoption could support a valuable materials, licensing or cell-supply business.
That is a conditional thesis, not an established result for either company. QuantumScape’s 2025 annual report identifies price, safety, energy density, charge rate and cycle life as competitive factors, alongside customer relationships and access to financial and manufacturing resources. It provides a useful scorecard; it does not independently establish that QuantumScape leads the field on those measures.
For a stock, technical promise is only one part of the equation. Investors also need evidence of repeatable production, customer qualification, commercial terms, revenue and a financing plan. Even genuine progress can fail to lift a share price if the company cannot execute, if competitors advance, or if the stock already reflects optimistic expectations.
What the latest company disclosures show
| Company | Technology and business approach | Partner evidence | Manufacturing evidence and limits | Financial context |
|---|---|---|---|---|
| QuantumScape (Nasdaq: QS) | Solid-state lithium-metal technology, as described in its investor-relations materials. | On June 18, 2026, QuantumScape announced a multi-year joint research agreement with Honda R&D after a technology evaluation. The announcement describes joint work; it does not disclose a mass-production order or guaranteed launch date. | The cited company materials establish development and partner research, but do not establish mass production of its cells. | Current share price, valuation and diluted share count are not established by the cited company materials. |
| Solid Power (Nasdaq: SLDP) | Sulfide electrolyte and cells; its 2025 Form 10-K describes electrolyte supply and licensing cell designs and manufacturing processes as central to its business model. | The Samsung SDI/BMW evaluation arrangement covers Solid Power electrolyte for Samsung SDI separator and/or catholyte and cell work, subject to technical requirements and partner assessment against agreed performance parameters. Solid Power’s August 4, 2026 release also described discussions about a potential Korean commercial-scale production joint venture; discussions are not a completed venture or supply contract. | Solid Power said its continuous electrolyte pilot line was targeted for validation and operational startup in Q4 2026. Its 2025 Form 10-K described planned capacity of up to 75 metric tons of electrolyte annually for that line. The timing was a company target and the capacity a design figure, not achieved output. The same filing described a possible Korean facility designed for up to 500 metric tons annually, also a plan rather than operating capacity. | For the first half of 2026, Solid Power reported $2.8 million in revenue and grant income, a mixed category that is not product sales alone. It reported $419.3 million in total liquidity as of June 30, 2026. For Q2 2026 it reported a $30.3 million operating loss and a $23.8 million net loss. These are company-reported figures, not a forecast of cash runway. |
Solid Power’s August 4, 2026 release also said site acceptance testing for the SK On line was completed in April 2026 and that the line-installation agreement was complete; negotiations for a new collaboration agreement were ongoing. Such equipment and negotiation milestones indicate activity, but do not by themselves establish customer qualification or commercial sales.
Revenue figures need similar care. Solid Power reported $21.7 million in revenue for 2025 in its 2025 Form 10-K, but that figure should not be treated as electrolyte product revenue without examining the revenue composition. Its disclosures describe collaboration, licensing or line-installation and grant-related sources. The company’s first-half 2026 figure likewise combines revenue and grant income; a $1.2 million reversal of previously recognized revenue followed changed assumptions about milestone payments.
Rank #2
- SEMI-SOLID-STATE SAFETY, BUILT FOR TRAVEL: Semi-solid-state cells hold a fraction of the flammable liquid in ordinary lithium-ion and resist thermal failure. In internal testing, the cells were puncture, cut and drill tested with no fire. The aluminum housing is highly thermally conductive, helping draw heat away from the cells and dissipate it during charging. Under 100Wh, it's airline carry-on ready.
- ALL-DAY POWER, STILL POCKETABLE: A full 10,000mAh gives a typical iPhone roughly 1.5 to 2 charges - plenty for long travel days, events and back-to-back workdays without chasing an outlet. The dense semi-solid state design (a paired 5,000mAh + 5,000mAh layout) keeps the pack slim enough to slip into a jacket pocket or bag. The built-in lanyard doubles as a USB-C cable, so a charging cord is always attached - nothing extra to pack or lose.
- QI2-CERTIFIED 15W MAGNETIC CHARGING: A strong, precisely aligned magnet snaps onto iPhone 17, 16, 15, 14, 13 and 12 with precise alignment and a strong hold, so you can keep using your phone while it charges. As a Qi2-certified, MagSafe-compatible charger, the magnetic connection keeps the charger aligned while you scroll, text, or move.
- DUAL USB-C, UP TO 30W OUTPUT: Two USB-C ports let you charge several devices at once and deliver up to 30W of fast wired power for phones, earbuds and tablets. The same port also refills the 10K itself quickly, so it's ready for the next day. (Large tablets and laptops draw more and may only charge partially.)
- FULL-COLOR LCD DISPLAY: A crisp color screen shows exact battery percentage plus live input and output wattage, so you always know how much power is left and how fast each device is charging - no blinking LEDs to decode. It stays easy to read at a glance, whether you're commuting, at an event, on a shoot or working late.
How to tell a partnership from commercial demand
Announcements can sound similar while representing very different levels of commitment. A research agreement or evaluation means technical work is under way; it is not equivalent to a purchase commitment. A customer’s decision to assess whether cells meet agreed parameters is a meaningful development step, but it is not proof that the customer will buy cells at scale.
- Research or evaluation: Check what is being tested, which partner is responsible for the assessment, and whether performance requirements have been met. QuantumScape’s Honda R&D agreement is described as joint research following an evaluation; Solid Power’s Samsung SDI/BMW arrangement involves technical requirements and partner assessment.
- Pilot equipment: Separate installation, acceptance testing, validation and startup from verified production. Equipment being installed or scheduled for commissioning does not show that it is producing saleable material at a useful yield.
- Qualification: Look for disclosed evidence that cells meet customer requirements and are accepted for a defined application. A company target or a partner evaluation alone does not establish qualification.
- Commercial commitment: Examine whether the company discloses binding purchase or supply terms, expected volumes, timing and who bears manufacturing responsibility. The relationships described above do not establish mass-production orders.
- Repeat economics: Track recurring product or license revenue, manufacturing consistency and the capital required to grow output. Grants and milestone-linked collaboration revenue are not the same as recurring product sales.
What could prevent the thesis from working?
Technical performance may not satisfy customers
Cells must deliver the required performance over repeated cycles and in the conditions relevant to a vehicle application. A target, lab result or promising sample is not the same as independently verified performance in a qualified product. QuantumScape’s 2025 annual report lists safety, energy density, charge rate, cycle life and price among the dimensions on which battery technologies compete.
Pilot success does not guarantee economical production
Moving from a pilot line to consistent, high-volume output can require process development, equipment, acceptable yields, quality systems and substantial capital. Solid Power’s Q4 2026 pilot-line startup was a target in its August 4, 2026 release, not a completed result. Its stated annual capacity figures describe plans or design capacity, not demonstrated economic output or customer demand.
Partner interest may not become a contract
Partners participate in evaluations and development for their own reasons, and they may control cell design, qualification and commercialization decisions. Solid Power’s 2025 Form 10-K says it must satisfy customer requirements, negotiate commercial terms and scale production—work that takes time and capital. A relationship can progress, change scope or fail to lead to a commercial agreement.
Funding, dilution and policy support matter
Development-stage companies can consume cash before sales scale. Solid Power’s 2025 Form 10-K says it had not generated cash flows from electrolyte sales or licensing sufficient to cover costs, and notes reliance on government contracts and grants for part of its revenue and research funding, with uncertainty around continued support. Its $419.3 million liquidity figure is a balance at June 30, 2026, not a precise runway estimate; runway depends on future spending, receipts and financing. Equity issuance can dilute existing shareholders.
Rank #3
- WORLD'S THINNEST SEMI-SOLID-STATE 5,000MAH: At just 6.8mm at its thinnest point, the Air is the slimmest semi-solid-state Qi2 power bank you can buy — the semi-solid-state design supports this slim form factor while helping the cells stay stable and reducing fire risk. It sits flush against your iPhone and slips into a pocket, slim bag or clutch. TechRadar Pro CES 2026 Picks Award Winner.
- SEMI-SOLID-STATE SAFETY, BUILT FOR TRAVEL: Unlike conventional lithium-ion banks with a flammable liquid electrolyte, SolidSafe Air's semi-solid-state cells sharply cut the liquid component — lowering risk at the cell level and staying stable under heat, stress and impact. It's not a circuit-only fix but a fundamental change in chemistry. At 18.5Wh, it's airline carry-on ready.
- 15W QI2 MAGNETIC + 20W USB-C: Qi2-certified, MagSafe-compatible magnetic charging snaps onto iPhone 17, 16, 15, 14, 13 and 12 with precise, secure alignment, while the USB-C port delivers up to 20W when you're in a hurry. The 5,000mAh cell gives a modern iPhone roughly one full top-up, and you can charge wired and wireless at the same time.
- TITANIUM SHELL, BUILT TO LAST: A titanium-reinforced shell resists dents and drops, and titanium's high thermal conductivity helps draw heat away from the cells and dissipate it at the surface during charging. It's premium protection that keeps the Air tough and travel-ready in a remarkably slim form.
- CCC CERTIFIED FOR TRAVEL: CCC certified for battery compliance and travel in China, with FCC, CE and UKCA listings for other regions. Built-in circuit safeguards cover overcharge, over-discharge, overcurrent and short circuits. Magnetic charging suits MagSafe iPhones or a thin compatible case; for Pixel and other Android phones, use a magnetic case or the 20W USB-C port.
Established competitors can improve too
Solid-state developers compete not only with one another but also with major battery suppliers, automakers and companies developing other battery approaches. Incumbents may have manufacturing experience, customer access and financial resources. Solid Power’s and QuantumScape’s corporate disclosures identify competition as broader than a single technical metric; no current independent product-leadership comparison is established by the company materials summarized here.
A practical framework for evaluating a solid-state stock
- Define the product: Is the company developing a lithium-metal cell, a solid electrolyte, a complete cell, or a licenseable process? Do not compare unlike business models as if they sell the same product.
- Place the milestone on a stage ladder: Distinguish lab results, customer samples, pilot equipment, line validation, vehicle demonstrations, customer qualification, commercial contracts, repeat production and recurring revenue.
- Read the partner’s role precisely: Identify whether the partner is evaluating, conducting research, installing equipment, qualifying a product or committing to buy it.
- Check manufacturing evidence: Compare stated capacity with actual output, yields, throughput and quality certification. Capacity on paper does not establish economic production.
- Assess financial durability: Review the latest cash and securities, quarterly cash use, grants, collaboration income, debt and equity issuance. A point-in-time liquidity balance cannot be converted into a reliable runway without cash-flow assumptions.
- Check valuation using current market data: Verify share price, diluted share count and market capitalization or enterprise value, then state the valuation method. The company milestones above do not establish whether QS or SLDP is cheap, expensive or likely to outperform.
- Compare adoption alternatives: Consider incumbent lithium-ion improvements and competing chemistries alongside solid-state proposals; vehicle-level cost, qualification and adoption evidence matter as much as cell-level promise.
Solid Power CEO John Van Scoter said in the company’s August 4, 2026 Q2 release: “We remain on track in advancing our new continuous manufacturing line and are progressing towards ISO 9001 certification as we further strengthen our commercial readiness and quality management system.” The statement describes the company’s progress and goals; certification and commercial readiness should be assessed against subsequent company disclosures.
Can these stocks be said to be poised to explode?
The evidence supports a plausible high-upside technology thesis, not a confident stock prediction. QuantumScape has a new multi-year Honda R&D research agreement; Solid Power has partner evaluations, line-related work and a planned pilot-line startup. Neither set of milestones, as described in the cited disclosures, proves mass production of solid-state EV cells or identifies a likely stock winner.
Calling either stock undervalued—or estimating how much it could rise—requires current share prices, diluted valuations and a consistent comparison with peers. Those figures are not established here. For investors, the central question is whether technical progress converts into qualified, repeatable production and durable commercial revenue before financing needs or competing technologies erode the opportunity.
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