Liuchuan Tong

Though it is often associated with news about smog, Beijing is neither the first nor the only city to be hit by it. The Great Smog of London covered the city in 1952. New Delhi and Mexico City frequently top “worst cities for smog” lists. Smog is often seen as an inevitable byproduct of economic development, but for Liuchuan Tong, a PhD candidate in chemistry and chemical biology, it doesn’t have to be. 

“One of the greatest challenges humanity faces this century is finding a clean energy source that can power a civilization of seven billion people,” Tong says. Solar energy is one such source and, in recent years, the cost of implementing it has tumbled. But a major barrier for solar’s adoption still remains: energy storage. “Storage is a major bottleneck because renewable energy is intermittent,” he says. “You don’t have solar energy at night. The energy is only there when Mother Nature wants it to be.

“We need a good method of energy storage to balance the system,” continues Tong. In the case of solar, excess energy would need to be stored during the day when there’s ample sunlight and later used at night. But where can the solar energy be stored? Batteries are an option, but not the type that power our remote controls and calculators. “These batteries are not great for energy storage,” he explains. “They’re expensive, they’re not scalable, and they’re highly flammable.” 

To develop a battery that solves all these issues, Tong has turned to nature, creating an organic flow battery that is easily scalable and, because the energy-storing components are dissolved in water, not flammable. “We’re using quinones, a class of organic molecules that can receive and release energy, which is exactly what a battery does,” he explains. A key advantage of quinones, which Tong likens to LEGO® pieces, is their malleability. “You can add different elements onto a quinone to tune its properties and make it more soluble, more stable,” he says. This proves to be a good characteristic, since transforming a quinone into a viable battery takes a lot of tinkering. “The concept of drawing inspiration from nature and using the quinone seems elegantly simple,” Tong adds. “But the actual development is hard.”