As a fifth-year PhD candidate in MIT’s Department of Materials Science and Engineering, Smith studies sodium-ion batteries, an emerging alternative to the lithium-ion batteries that power everything from smartphones to electric vehicles. “I’ve believed for a very long time that the biggest engineering problem humanity faces is the transition to clean energy,” Smith says. Consumers often want batteries that charge quickly, last for years, store large amounts of energy, and remain inexpensive. “It’s not catering extremely to some properties and then abandoning others.”The sodium-ion batteries Smith studies could eventually provide lower-cost options for electrical grids or more affordable electric vehicles. Because sodium-ion batteries can largely be manufactured using the same infrastructure already developed for lithium-ion batteries, they also offer a potentially smoother path toward commercialization than many emerging battery technologies.