Shriram Ramanathan at the Harvard School of Engineering and Applied Sciences (SEAS) is an expert and innovator in the development of solid-oxide fuel cells (SOFCs).
Reliability, temperature, and cost are the main obstacles in using SOFCs to charge laptops and phones. They operate by converting chemical energy (from hydrogen or a hydrocarbon fuel such as methane) into an electric current.
Now, Ramanathan's group has demonstrated stable and functional all-ceramic thin-film SOFCs that do not contain any platinum. In thin-film SOFCs, the electrolyte is reduced to a hundredth or even a thousandth of its usual scale.
"If you use porous metal electrodes, they tend to be inherently unstable over long periods of time. They start to agglomerate and create open circuits in the fuel cells," said Ramanathan.
Ramanathan's platinum-free micro-SOFC eliminates this problem - resulting in lower cost and higher reliability.
Another study by his group demonstrated a methane-fueled micro-SOFC operating at less than 500 degrees Celsius. When fuel cells operate at lower temperatures, material reliability is less critical-allowing, for example, the use of less expensive ceramics and metallic interconnects-and the start-up time can be shorter.
"Low temperature is a holy grail in this field. If you can realize high-performance solid-oxide fuel cells that operate in the 300 degrees C range, you can use them in transportation vehicles and portable electronics, and with different types of fuels," he said.
Another plus is the use of methane, an abundant and cheap natural gas.
"Future research at SEAS will explore new types of catalysts for methane SOFCs, with the goal of identifying affordable, earth-abundant materials that can help lower the operating temperature even further," added Ramanathan.