Advanced Li-ion and multivalent ion batteries. The work on advanced lithium ion and multivalent ion batteries is led by Yet-Ming Chiang, the Kyocera Professor Department of Materials Science and Engineering at MIT, and Evgeny Antipov, professor and electrochemistry chair at Moscow State.

Among the subjects of interest in this area are advanced electrode materials (such as LiMPO₄, LiMBO₃, Li₂MPO4F, LiV₂O₅: high-voltages and/or high capacity); advanced electrolytes and solvent-electrode interfaces; multivalent ion batteries; novel microporous separators; new proton conductive composite membranes specially designed for redox systems.

Chiang, MIT colleague W. Craig Carter, with their associates, published a study in Advanced Energy Materials (Li et al.) showing use of aluminum ions as an energy-storage mechanism in a capacitor. Aluminum is more abundant and less costly than lithium.

The aluminum ion research fits into a quest to find battery materials that pack higher charge density than lithium. The advantage of aluminum is that it carries three charges per ion compared with lithium, which carries just one. This allows storage of charge at a higher volumetric or gravimetric density, which translates to a higher stored energy density or storage capacity for a given size or weight. Other work focuses on sodium as an earth-abundant alternative to lithium, but while it could lower cost, sodium ions also carry just a single charge.

Rechargeable metal-air batteries. The work on rechargeable metal-air batteries is led by MIT Professor Yang Shao-Horn and Evgeny Goodilin, professor and deputy dean of materials science at Moscow State.

The metal-air thrust is examining whether a metal-air battery that stores lithium in the form of its oxide, lithium peroxide (Li₂O₂), with potential for greatly enhanced energy storage density, can be made to function reversibly.

Areas of research include, but are not limited to: synthesis of nanostructured oxide catalysts/electrodes; in situ studies of electrochemical reactions and chemical reactivity; novel electrode designs; solvent influence on redox potentials; nucleation and growth of Li₂O₂/Na₂O; in situ TEM studies of electrode-water interface; and in situ XANES of oxides.

Reversible fuel-electrolysis cells. The reversible fuel-electrolysis cells work is led by Harry Tuller, professor of ceramics and electronic materials at MIT, and Evgeny Antipov at Moscow State.

This area currently has three areas of focus:

• Intermediate temperature solid oxide fuel cells;
• Polymer electrolyte fuel cells; and
• Reversible fuel/electrolysis cells.

High-temperature solid-oxide fuel cells and solid-oxide electrolysis cells have potential over the intermediate term to double energy efficiency from fossil fuels and reduce greenhouse gas emissions as well as over the long-term to enable the shift to renewable energy sources such as solar and wind. A solid oxide fuel cell-electrolysis thrust aims to optimize conversion efficiency between chemical and electrical energy, lower operating temperatures to increase the lifetime of these devices, and bring down costs.

We need a way of producing alternative cleaner fuels, minimizing use of hydrocarbons, or at a minimum recycling the carbon dioxide to form these more useful fuels. High-temperature systems really offer a number of advantages in terms of actually being able to do that, particularly decomposing carbon dioxide, but also doing so with less costly materials and more efficiently.

—Harry Tuller

Because solar and wind energy are intermittent, producing energy only when the sun shines or the wind blows, a method to capture and store energy for later use is needed. Fuel cells, coupled with electrochemical electrolysis, have potential to serve that role. One way is to generate hydrogen by splitting water and storing the hydrogen, as in the power-to-gas schemes under examination (e.g., earlier post).

The challenge with hydrogen is that while it has a high energy density on a weight basis, it has a very low energy density based on a volume basis, and the infrastructure that we now have is not particularly designed to transmit that hydrogen over long distances. So ideally what you’d prefer is something that more closely resembles conventional fuels.

If we could take CO₂ which is now problematic, and use some sort of technique to decompose CO₂ back into, for example, carbon monoxide [CO], then there are a variety of different ways in which you can react hydrogen and the CO to produce gaseous fuels like methane or liquid hydrocarbon fuels. The big advantage there is if you can convert that back into synthetic gas, which resembles natural gas, or a liquid fuel, like gasoline, then we have this enormous infrastructure already available nationwide and world-wide where we can store it, transmit it and use it in many different ways, including for transportation. We can use it in vehicles, we can use it in aircraft, and so forth.

—Harry Tuller

Electrolyzers operating in the 100-degrees Celsius range, such as polymer electrolyte-based cells, can split water, but they can’t very efficiently decompose CO₂, Tuller says. Likewise polymer electrolyte membrane (PEM) fuel cells operate only with H₂ as the fuel and only then with platinum electrodes. Solid-oxide-based cells operating at high temperature are more efficient and can operate with lower-cost metal oxide catalysts versus more expensive platinum. But the solid-oxide materials are more difficult to fabricate, which increases cost, and higher temperatures accelerate certain reactions that shorten operating life.

We’re looking to try to understand in more detail what are the sources of degradation and what are the factors which limit performance at lower temperatures.

—Harry Tuller

The researchers are creating model systems for fuel cell structures to do a better job of isolating factors that contribute to performance and investigating novel materials with promising features in terms of both endurance and performance.

In particular, the researchers are looking at modifying the morphology of the electrode materials to enhance transport of gas molecules through their pores, flow of ions and electrons through the solid part of the electrode, and catalytic activity at the electrode interface.

A patent disclosure related to the electrode material morphology work is expected in the next month or so, Tuller says.

CEES. Altogether, eight MIT faculty members and eight Moscow State University faculty members are engaged in CEES-related research.

Within MIT, there are people from materials engineering, mechanical engineering, chemical engineering and chemistry, says Carl V. Thompson, co-director of CEES and the Stavros Salapatas Professor of Materials Science and Engineering at MIT as well as director of the Materials Processing Center. Thompson previously served from 2000 to 2014 as co-chair of the MIT Singapore Alliance’s Program in Advanced Materials for Micro- and Nano-Systems.

Skoltech MIT Center for Electrochemical Energy Storage got started in October 2013 and completed its first full year in 2014. So far, just a small number of students from Skoltech have come to MIT, usually first-year master’s degree students, but Thompson anticipates that over time more master’s and PhD students will be doing research at MIT.

Visits to MIT by Skoltech CEES Director Keith Stevenson and Moscow State University faculty have yielded insights into different materials that operate better at much lower temperatures for different applications and optimizing material properties by manipulating complex crystal chemistries, Tuller says.

CEES also has a Russian co-director, Alexei Khokhlov, who is professor and head of polymer physics as well as vice-rector at Moscow State University. He leads the research team at Moscow State. MIT CEES Assistant Director Jack Kosek is responsible for budgeting, reporting, and managing timetables.

The Skoltech-MIT CEES partnership is expected to run for five years. CEES is part of the larger Skoltech effort to create a Silicon Valley-like innovation hub in Russia by pairing the fledging graduate-level institute with an industrial and commercial park setting. The Russian economy is currently heavily dependent on selling carbon-based fossil fuels, principally oil and gas.

For Russia to have economic stability and balanced relationships with other nations, it’s important for its economy to become more diverse and more broadly integrated with the rest of the world.

—Carl Thompson

Resources

• Li Z., Xiang K., Xing W., Carter W. C., Chiang Yet-Ming (2015). “Reversible Aluminum-Ion Intercalation in Prussian Blue Analogs and Demonstration of a High-Power Aluminum-Ion Asymmetric Capacitor.” Adv. Energy Mater., 5 doi: 10.1002/aenm.201401410