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The rocket scientist behind the Super Soaker is developing a new battery

Prototype batteries made by Johnson Battery Technologies, the lab of inventor Lonnie Johnson.Prototype batteries made by Johnson Battery Technologies, the lab of inventor Lonnie Johnson.
Prototype batteries made by Johnson Battery Technologies, the lab of inventor Lonnie Johnson.Courtesy of Johnson Battery Technologies

What does the Super Soaker water gun have to do with new innovative batteries? A lot, it turns out.

The proceeds of the massively successful water toy have been helping a new type of battery get to market.

Inventor Lonnie Johnson, a nuclear engineer by training, has spent decades developing new technologies like an advanced heat engine and nuclear power for space craft while he was at NASA. He’s now working on a safer and better performing battery that, if successful, could create a new way to store energy for mobile devices, off-grid oil fields, and electric cars.

In the 1980’s, while working on a new type of water-based heat pump in his spare time, Johnson stumbled across water stream technology that he thought would make a fun water gun. He eventually licensed it to Larami Corporation, later acquired by toy giant Hasbro, which turned the idea into the hit toy.

Sales of the Super Soaker have reportedly reached $1 billion. Hasbro also used Johnson’s propulsion technology in its Nerf toy gun line.

Johnson used his earnings from the water gun to start his own invention shop called Johnson Research and Development. Over the years he plowed much of his Super Soaker profits into energy research and development, including a new type of heat engine prototype that can, in theory, more efficiently convert heat into electricity.

He went into debt in the process. But two years ago, Johnson won another $73 million in a royalty dispute with Hasbro and again invested a big chunk of that into keeping his lab — set up on four acres in the Southside of downtown Atlanta — up and running. It employs 20 people.

Inventor and entrepreneur Lonnie Johnson. Courtesy of Johnson Battery Technologies
Courtesy of Johnson Battery Technologies

Now Johnson is working on commercializing his battery technology, which he hopes to start selling in less then a year. Oil giant BP (BP) has agreed to test the batteries in remote oil fields after the technology becomes available. BP has also contributed funding to the battery project.

“The battery is our number one priority right now,” Johnson told Fortune.

Johnson’s battery, called a “solid-state lithium metal” battery, uses ceramic for the electrolyte part of the battery. The electrolyte is the medium through which lithium ions charge and discharge between the battery’s electrodes. Traditional lithium ion batteries use a liquid or a gel for the electrolyte, and as a result can be far more flammable.

The new material used in Johnson’s battery is able to operate safely at much higher temperatures than standard lithium ion batteries. BP approached Johnson for a battery that could operate at temperatures over 150 degrees centigrade on its oil infrastructure.

Solid-state batteries are considered to be an important step beyond the lithium-ion battery. Startups like Sakti3 have been working on solid-state batteries that can be safer, lower cost and deliver better performance.

In addition to safety, Johnson says his battery can store three times the energy of the conventional lithium-ion version. If used in a Tesla car, his battery could deliver a range of 1,000 miles, instead of the Model S’s current 300-mile range. In a cell phone, or a wearable device, such a battery could mean a much longer time between charging.

To make the battery, Johnson used early research from Oak Ridge National Labs. But that initial technology was expensive to manufacture and difficult to mass produce. In addition, many years ago — before the rise of consumer electronics powered by lithium ion batteries — there wasn’t really a market.

In recent years, Johnson has started using ceramic industry manufacturing techniques to lower the cost. For the next stage of development, Johnson is looking to partner, work with contract manufacturers, and raise money from investors to start making and selling the battery. But for now, his technology is still at an early phase.

Developing new batteries is a notoriously difficult business for startups. Investors, at least in Silicon Valley, have been shying away from funding battery technology in recent years due to the high risk nature. However, venture capital-backed battery startup Seeo was recently acquired by auto giant Bosch in a rare win for investors.

In addition to his own funds, Johnson has been using grants from the Defense and Energy Departments to keep the research going. It hasn’t been easy.

But Johnson —an African-American born in Alabama in 1949 during legal segregation – is no stranger to overcoming adversity. According to Biography, in high school he won the state science fair competition by building a compressed-air-powered robot. The competition was held at University of Alabama at Tuscaloosa, where a few years earlier the Governor tried to prevent two African-American students from enrolling in the school.

Johnson hasn’t stopped taking on challenges that many would not. In addition to this battery, he also wants to build a prototype of his heat engine that he can show to partners and investors, to help them see its potential. Some in the scientific community have been skeptical of the idea. “I want something to share so people can feel and touch it,” said Johnson.

Despite the challenges, it’s a good time to be in the energy storage industry. Consumer electronics companies are seeking new ways to power smaller devices for longer periods of time. Apple has been investing heavily in battery technology, both buying startups and building battery tech in house.

In addition, the markets for electric cars and grid batteries — which can store solar energy at night or help utilities better manage the power grid —are just getting started. In the U.S. this year there’s supposed to be 220 megawatts of energy storage projects built across the country, according to research firm GTM Research. That’s enough energy stored to power about 220,000 average homes.

For the past decade, Johnson has had a strategy of using his profits from consumer tech — the Super Soaker toy — to fund his other world-changing tech. It’s somewhat similar to how Elon Musk used his proceeds from digital payment service PayPal to make electric cars at Tesla , solar panels at SolarCity and rockets at SpaceX.

When I ask Johnson how he feels about using the Super Soaker as an avenue to his world-changing and hard-core science ideas, he laughs. “Once I get the engine done, maybe I’ll go back to working on some consumer technology. It’s probably easier to make money in.”

To learn more about batteries watch this Fortune video: