QuantumScape Corp. is the hottest battery-maker on the market, with recent valuations hovering between $13 billion and $20 billion. While the San Jose, California-based startup says its next-generation battery will increase the range of an electric car by as much as 50% and reduce the charging time to less than 15 minutes, it’s been tight-lipped about how. The battery industry is highly secretive, and much of QuantumScape’s future success depends on its ability to protect its technology and retain top talent. With little standardization and no way to test claims, it’s hard for speculators in the space to judge the true risk of their investments. The combination of hype and mystery is always intoxicating for short sellers, and QuantumScape has proved no exception. Just shy of two weeks ago, activist firm Scorpion Capital issued a report calling the company a “scam.”

At the Bloomberg Green Summit, Akshat Rathi spoke with QuantumScape Chief Executive Officer Jagdeep Singh about the company’s 10-year journey, the difficulty of innovating in battery materials, and the challenge of dealing with a short-seller attack while maintaining investor trust.

Here are some of the highlights from the conversation:

relates to QuantumScape Defends Its Battery Breakthrough Against the Short Sellers

Jagdeep Singh: I had just purchased a Tesla Roadster after it was introduced in 2008. You could argue that it was the future of cars: fast, fun, clean. But all its limitations stemmed from batteries. I got somewhat obsessed with trying to solve the problem. I became convinced that the battery problem may be the biggest unsolved problem in all of technology.