Math model to help design new materials for storing electricity

Researchers have devised a mathematical model for designing new materials for storing electricity, an approach different from chemists and materials scientists who traditionally rely on trial and error to create materials for batteries and capacitors.

"The potential here is that you could build batteries that last much longer and make them much smaller," said Daniel Tartakovsky, a professor in the School of Earth, Energy & Environmental Sciences at Stanford University and co-author of a study published this week in Applied Physics Letters. "If you could engineer a material with a far superior storage capacity than what we have today, then you could dramatically improve the performance of batteries."

Advancing new materials for energy storage is an important step toward reducing carbon emissions in the transportation and electricity sectors. One of the primary obstacles to transitioning from fossil fuels to renewables is the ability to store energy for later use, such as during hours when the sun is not shining in the case of solar power.

The study, "Optimal design of nanoporous materials for electrochemical devices," is expected to help improve supercapacitors, a type of next-generation energy storage that could replace rechargeable batteries in high-tech devices like cellphones and electric vehicles. Supercapacitors combine the best of what is currently available for energy storage -- batteries, which hold a lot of energy but charge slowly, and capacitors, which charge quickly but hold little energy.

The materials must be able to withstand both high power and high energy to avoid breaking, exploding or catching fire.

"Current batteries and other storage devices are a major bottleneck for transition to clean energy," Tartakovsky was quoted as saying in a news release from Stanford. "There are many people working on this, but this is a new approach to looking at the problem."

The types of materials used to develop energy storage, known as nanoporous materials, look solid to the human eye but contain microscopic holes that give them unique properties. To develop possibly better nanoporous materials, the current method, involving arranging minuscule grains of silica of different sizes in a mold, filling the mold with a solid substance and then dissolving the grains to create a material containing many small holes, requires extensive planning, labor, experimentation and modifications, without guaranteeing the end result will be the best possible option.

"We developed a model that would allow materials chemists to know what to expect in terms of performance if the grains are arranged in a certain way, without going through these experiments," said Tartakovsky, whose mathematical modeling research spans neuroscience, urban development, medicine and more. "This framework also shows that if you arrange your grains like the model suggests, then you will get the maximum performance."

As an Earth scientist and professor of energy resources engineering, Tartakovsky is an expert in the flow and transport of porous media. Notifying that energy is just one industry that makes use of nanoporous materials, Tartakovsky hopes his model will be applicable in other areas. Endit