Héctor D. Abruña, Chemistry and Chemical Biology, is emphatic in his vision for our energy future. “Make no mistake, transportation will be electric. Period,” says Abruña. “It’s not a matter of if, it’s a matter of when. The difference will be dramatic in 10 years.”
Other advances will include batteries hitting mainstream applications across the board, from transportation to large-scale energy grid applications. The “automotive range anxiety” (in other words, the fear of not having enough charge to get to your destination) of today’s battery-powered cars will be no more. The energy grid will integrate renewables—solar, wind, tidal—and will be able to efficiently and effectively store electrical energy, thanks to new materials and technologies.
Abruña is dedicated to energy research, and as an electrochemist, his work is at the heart of virtually all energy-related systems. Electrochemistry is the study of chemical reactions at the interface between electrodes—usually metals—and electrolytes—the conducting solutions. This research covers such energy systems as batteries, fuel cells, and molecular electronics, all of which Abruña’s lab studies.
Energy Research, a Collaborative Venture
Most of the lab’s work is focused on developing better and new materials to enhance the performance of batteries and fuel cells. To accomplish this task, Abruña collaborates extensively with other researchers across disciplines to advance energy science.
Abruña collaborates with David Muller and Joel Brock, Applied and Engineering Physics, to study energy systems in operando, meaning under actual operating conditions. Muller is an electron microscopist, and Brock is the Director of the Cornell High Energy Synchrotron Source (CHESS). Together, they have developed ways to leverage such techniques as electron microscopy and x-ray diffraction and absorption spectroscopy to take a look at what’s going on inside batteries and fuel cells.
“Batteries have very reactive interfaces, and if you take them apart and pretend like nothing changes, you’re fooling yourself,” says Abruña. “If you really want to understand the mechanisms through which these things work, you have to use operando methods. We developed a set of tools that are unique within this framework.”
Abruña and his colleagues want to understand the atomic- and molecular-level processes involved. Such studies will enable the fundamental breakthroughs, rather than small incremental improvements, that are critical to engineering dramatically better performing materials and devices.
Abruña has also collaborated closely with Geoffrey Coates, Chemistry and Chemical Biology, in the development of alkaline membranes for fuel cells. These membranes would make fuel cells far more affordable, as they would not require electrodes to be made up of the expensive precious metals that are used today. The two labs are working together to make better performing alkaline membranes and to integrate them into membrane electrode assemblies (MEAs), which are the heart of a fuel cell.
Finally, in the area of molecular electronics, Abruña has worked with Will Dichtel, Chemistry and Chemical Biology, and Daniel Ralph, Physics. The idea with this team is to use graphene, a novel nanomaterial, as an electrode. He and Ralph established the fundamental behavior of single layer graphene as an electrode. Dichtel designed molecules that can provide an electrical signal and move on the surface of graphene. Abruña’s group then measured the two-dimensional movement of the molecules on the surface. The material could be used in sensor devices and microfluidics. But mostly, Abruña sees it as an experimental platform with which researchers can use electrochemical methods to model interfacial problems in numerous applications.
What’s clear is that the energy problems the world faces today are much too big for just one research group to solve on its own. That’s Abruña’s premise. “It involves a lot of people’s research, but the basic idea is to work together,” says Abruña. “One of the hallmarks of Cornell is its collaborative environment. We have people who do theory, synthesis, and characterization. That allows us the ability to really tackle big problems that no individual group would be able to do.”
Lithium-Sulfur Batteries
Abruña’s group has made particularly impressive strides in lithium-sulfur batteries, one of the more promising alternatives to today’s lithium-ion batteries. Lithium-sulfur batteries use sulfur as the cathode (the positive-end electrode) and lithium as the anode (the negative-end electrode). The batteries have a high theoretical capacity, which means they can offer around five times the energy of conventional lithium-ion batteries. The main problems have been sulfur’s complex and slow reduction–oxidation (redox) reactions as well as dissolution of the electrogenerated polysulfides.
To stabilize the sulfur and polysulfides in the batteries, Abruña’s lab added amylopectin, a polysaccharide found in cornstarch. The researchers found that the addition helped improve the cycling stability of the battery. In another discovery, they made battery cathodes using a sulfur-polyaniline composite (polyaniline is a conductive polymer). The new method and material made it possible for the battery to have excellent cyclability with small capacity losses.
The Startup, Lionano
The Abruña group has also developed a very high performance anode material for lithium-ion batteries based on mixed transition metal oxides. This discovery has been patented through the Center for Technology Licensing (CTL) and licensed by Cornell to a startup company: Lionano. Lionano’s cofounders include a former graduate student from Abruña’s lab, Yingchao Yu. Abruña also advises the company. Lionano has already partnered with the New York State Energy Research and Development Authority and won energy contests and awards, including PowerBridgeNY and the North American Professionals and Entrepreneurs Council (NAPEC) Innovation Challenge.
Acquiring the Tools to Tackle the Big Problems
Abruña got his start in electrochemistry as an undergraduate at Rensselaer Polytechnic Institute, when he met a professor in the field. “I just thought he was so smart,” says Abruña, although he also says that, unfortunately, electrochemistry at the undergraduate level tends to be rather boring.
“One of the hallmarks of Cornell is its collaborative environment. We have people who do theory, synthesis, and characterization. That allows us the ability to really tackle big problems.”
In graduate school, at the University of North Carolina at Chapel Hill, Abruña had the opportunity to address much more interesting problems, and best of all, he says it’s a field that borrows from many others. “It serves as a gateway to talking to chemists, physicists, materials scientists, and more.”
Today, one could say that Abruña plays the same role as his former professor, inspiring students to go into electrochemistry and make an impact.
“The purpose of a research education is to provide you with the tools to address problems,” says Abruña. “The nature of the problems changes because the nature of the times changes. Energy, broadly defined, is a very real problem and one to which electrochemistry can provide a great deal of insight.” His lab includes around 20 researchers made up of postdoctorates, graduate students, and a couple of undergraduates. And each plays a critical role in advancing the lab’s research.
“We’re blessed with very good students and postdocs,” says Abruña. “As much as I work, I wake up in the morning wanting to go to work. It’s the ultimate gift.”