After a 100% Gain Last Year, Can QuantumScape Soar Again in 2026?

Investors have been speculating about QuantumScape (NASDAQ: QS) stock for nearly five years now. Shares are down 80% over those five years after excitement surrounding its solid-state battery technology drove the stock to unsustainable levels following the company's initial public offering (IPO) in late 2020.

Now that the company has taken concrete steps toward successfully commercializing its technology, investors are jumping back in. That led to a 100.8% gain in 2025, according to data provided by S&P Global Market Intelligence. Now investors want to know if that could be just the beginning.

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Momentum picking up

QuantumScape shares were relatively flat for the first half of 2025. The stock broke out in July, however, after the company announced it was expanding its collaboration and licensing arrangement with Volkswagen Group's battery company, PowerCo. More than just bringing in additional capital, the agreement is intended to expedite the development of QuantumScape's battery pilot line in California. It's an essential step toward industrializing solid-state battery technology.

Other milestones that drove momentum in the stock were agreements announced with glass and ceramics maker Corning and electronics manufacturer Murata Manufacturing for high-volume production of its ceramic separators.

QuantumScape's latest advancement

Another stock-moving milestone was the start of shipments of initial samples of QuantumScape's battery cells to customers for testing. That was a key 2025 goal the company achieved in the third quarter.

QuantumScape's batteries should offer higher energy density, quicker charging, and enhanced safety on a large scale compared to traditional lithium-ion cells. The company has been working on its separator process, a faster, continuous manufacturing technique that produces ultra-thin solid-state separators on a mass scale. The agreements and partnerships announced last year are now in place to achieve that goal.

2025 marked the year QuantumScape showed it could expand its technology. It now has sights set on attaining automotive-grade reliability by setting up a highly automated cell-production pilot line, known as the Eagle Line, at its headquarters in San Jose, California. Additionally, it has revealed a new joint development agreement with an automotive original equipment manufacturer (OEM) customer -- another goal it had set for 2025.

Will the stock double again?

Even considering these accomplishments, QuantumScape remains a very risky stock. Investors should almost view the potential outcomes as binary. If automakers approve its technology and deliver the benefits demonstrated in the laboratory, the company could become a leading global supplier to EV manufacturers. It already has a partner in Volkswagen, and other automakers would likely line up for the product.

However, if another technology surpasses its solid-state battery, or the company runs into issues producing at volume, the stock could easily tank. Investors should be sure to enter with both possible outcomes in mind.

Howard Smith has positions in QuantumScape. The Motley Fool has positions in and recommends Corning. The Motley Fool recommends Volkswagen Ag. The Motley Fool has a disclosure policy.