The world of technology constantly craves progress, and one of the most critical areas where innovation is not only desirable but necessary is energy storage. Our modern batteries, despite decades of refinement, often struggle to keep pace with the growing demands of advanced technologies like electric vehicles or applications in extreme conditions. But in this challenging environment, ideas are born that have the potential to fundamentally change the game.

One such spark of innovation flashed at the University of California San Diego (UC San Diego), fueled by the unusual curiosity of a graduate student. Observing an ordinary can of compressed air for cleaning keyboards, he wondered if a similar principle could be applied in the world of batteries. This initial idea, supported by a university ecosystem that fosters research and creative freedom, grew into a promising new battery technology capable of significantly improving battery performance, safety, and versatility. This story illustrates how fundamental curiosity, with adequate support, can lead to revolutionary discoveries.

The Need for an Energy Renaissance in the Battery Industry

Existing lithium-ion technology, commercialized more than three decades ago, faces inherent limitations. Although significant improvements in energy density and cost reduction have been achieved, largely thanks to advances in manufacturing processes, the fundamental chemistry – which relies on a graphite anode, a metal oxide cathode, and a liquid electrolyte – has remained largely unchanged. Originally designed for consumer electronics like mobile phones and laptops, these batteries are now being massively integrated into much larger systems, such as electric vehicles, which necessitates radical changes in chemical composition.

Experts worldwide are exploring various alternatives, including silicon anodes, sulfur cathodes, and solid-state electrolytes. Each of these approaches has its own advantages and disadvantages. For example, solid-state electrolytes promise higher energy density and safety, but their mass production could be more expensive and require longer development times. Therefore, the search for a transformative technology that will meet future energy needs is more intense than ever. It is likely that a combination of multiple technologies will be used for different applications – high-end electric vehicles, more affordable cars, aircraft, and drones will have specific requirements that today's technology can hardly meet.

South 8 Technologies: Revolution with Liquefied Gas

In this dynamic environment, South 8 Technologies stands out, a startup founded and led by former UC San Diego students. Their most significant contribution is the patented Liquefied Gas Electrolyte (LiGasⓇ) technology, which was recognized as one of the 200 best inventions of 2024 by TIME magazine. By replacing conventional liquid electrolytes in lithium-ion batteries with liquefied gases, South 8 batteries achieve a world record in operational temperature range: from -60 to +60 degrees Celsius. For comparison, standard lithium-ion batteries lose performance already at 0 or -10 degrees Celsius.

In addition to impressive temperature resistance, these batteries also offer higher energy density per cell and significantly improved safety. Cyrus Rustomji, Chief Scientific Officer and co-founder of South 8, who earned his PhD from the Jacobs School of Engineering at UC San Diego in 2015, emphasizes another key advantage: the materials needed for LiGasⓇ battery production, including commercially available industrial gases, are produced in large quantities within the USA. This eliminates dependence on foreign suppliers, which is a significant step towards energy independence and supply chain security. Rustomji co-founded the company with a colleague, also a former nanoengineering student at UC San Diego, Jungwoo Lee.

From a Can of Compressed Air to a Technological Breakthrough

The initial discovery that led to LiGasⓇ technology occurred during Rustomji's doctoral studies at UC San Diego. As he says, the idea came to him while sitting at his desk. "You might be familiar with those small cans of compressed air used to clean keyboards. I was looking at one and wondered what was actually inside. I turned the can over and read: 'difluoroethane'."

Difluoroethane, as Rustomji quickly realized, is a unique gas that can be liquefied under moderate pressure. It is non-toxic but sufficiently polar to dissolve salts, a key property for an electrolyte. Since it is essentially a gas, it does not freeze until extremely low temperatures. "I wondered if this could enable the creation of a low-temperature electrolyte – liquid inside the cell under pressure – and thus open up space for battery applications that operate at ultra-low temperatures," Rustomji recalls. Further research confirmed his assumptions, revealing extraordinary performance at low temperatures.

Over time, the team realized that this technology also offers other advantages, such as greater safety, energy density, and fast charging capabilities, which is particularly important for electric vehicles. "We realized we could really do something with this," says Rustomji. The decision to found South 8 Technologies was a logical next step, with the goal of commercializing this promising technology.

The Role of University Support and Funding

The development of LiGasⓇ technology would not have been possible without the strong support of the University of California San Diego. Rustomji highlights the excellence of its engineering school and the invaluable mentorship of nanoengineering professor Shirley Meng, a world-renowned expert in battery materials. Her guidance enabled him to gain a fundamental understanding of the current state of battery technology and future needs.

Access to state-of-the-art equipment and resources was also crucial. The Nano3 nanofabrication cleanroom facility, whose establishment was largely funded by the National Science Foundation (NSF), was instrumental in the early stages of understanding battery technologies. "Nano3 has an excellent selection of spectroscopic and metrology tools, such as SEM (scanning electron microscope), FIB (focused ion beam), and E-beam (electron-beam lithography), which greatly helped us understand the fundamental interactions within the battery device," explains Rustomji. "UC San Diego simply has great tools that enable a better fundamental understanding of the advanced materials we were developing. Without these capabilities and instruments, we wouldn't be where we are today."

Collaboration was not limited to UC San Diego. The team also used laboratories at the nearby University of California Irvine (UC Irvine) for characterization using transmission electron microscopy (TEM). The Materials Research Institute at UC Irvine is also partly supported by the NSF, indicating the strength of the collaborative network within the University of California system.

Numerous professors from the campus, including Ping Liu, Shirley Meng, and Zheng Chen (all from the Aiiso Yufeng Li Family Department of Chemical and Nano Engineering), readily provided assistance and collaborated on the project. Regarding financial resources, even while Rustomji was a graduate student, the team secured funding from ARPA-E (Advanced Research Projects Agency-Energy). "The Department of Energy funded us with a small grant, which really spurred this innovation and allowed me to dedicate myself full-time on campus to applications and technology," Rustomji points out. During his postdoctoral studies, he successfully applied for Small Business Innovation Research grants from the NSF and NASA. These funds enabled the completion of his postdoctoral work and full dedication to the company.

Applications and Future of LiGasⓇ Technology

The ability of LiGasⓇ batteries to operate in extreme cold has attracted the attention of the U.S. military, which is testing them to power communication devices in ultra-cold regions. Contracts with the military confirm the robustness and reliability of the technology in the most demanding conditions. Automotive companies are also showing significant interest, recognizing the potential of these batteries to advance the electric vehicle market, particularly in terms of range and performance in various climatic conditions, and safety.

South 8 Technologies, headquartered in San Diego, California, proves that even areas not known for extreme temperatures can be fertile ground for developing solutions designed for precisely such conditions. Rustomji jokes that he doesn't like the cold, so he wanted to find an energy solution for it. But, speaking more seriously, the ecosystem in Southern California, particularly in San Diego, has proven to be extremely favorable.

"First, there's UC San Diego, which also includes the Rady School of Management. Nearby is San Diego State University, which also educates talented engineers and scientists. We've had graduates from both universities join our team," says Rustomji. "San Diego offers much more than pleasant weather."

Additional support is provided by the Southern California Energy Innovation Network (SCEIN), a network that connects local entrepreneurs, enables the exchange of information about funding opportunities from federal or state sources, and helps connect with venture capitalists. "This networking opportunity has been truly invaluable," adds Rustomji. "I think San Diego is often underestimated as a hub of innovation and entrepreneurship. But many great things are being done here, not only in clean technology but also in the hardware and software industries. A lot of great innovation is happening in San Diego."

Messages for Future Innovators

Next year, South 8 Technologies will celebrate its tenth anniversary as a startup. When asked what advice he has for aspiring engineers and entrepreneurs thinking about starting their own companies, Rustomji replies: "Be in love with what you do and love the people you do it with. It's going to be a journey, not a sprint. And only those who love what they do and who they do it with will be successful at the end of the day."

And what would the perfect battery be, and will we ever create it? "The perfect battery would be inherently very safe, would never discharge, would just charge and discharge over and over again for millions of cycles, would charge as fast as you want, and would cost almost nothing," says Rustomji. "But the fun in being a scientist or engineer is knowing that's a dream. The fun is in getting better and better, getting as close as possible to that dream battery and making those improvements. Otherwise, if the perfect battery existed, it would take the fun out of the innovation process. And that can be applied to any technology. Nothing is ever perfect, and I think it's precisely imperfection that makes innovation so fun."

The development of technology like LiGasⓇ shows that we are on the right track towards solving some of the biggest challenges in energy storage, opening doors to new possibilities in numerous industries and bringing us closer to a future with more reliable, safer, and more versatile battery solutions.

Source: University of California