Apr 7 2017
A recent Stanford study illustrates a mathematical model for designing innovative materials used in electrical storage devices, such as capacitors and car batteries. This method may greatly quicken discovery of new materials that offer efficient and economical ways to store energy.
The research has been published this week in Applied Physics Letters. The mathematical model could be a big advantage to materials scientists and chemists, who traditionally depend on trial and error to develop new materials for capacitors and batteries. Advancing new materials for energy storage is a significant step toward decreasing carbon emissions in the electricity and transportation sectors.
The potential here is that you could build batteries that last much longer and make them much smaller. 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.
co-author Daniel Tartakovsky, a professor in the School of Earth, Energy & Environmental Sciences.
Lowering a barrier
One of the main hindrances to transitioning from fossil fuels to renewables is the inability to store energy for later use, such as when the sun is not shining in the case of solar power.
Demand for economical, efficient storage has grown as many companies are turning to renewable energy sources, which offer major public health benefits.
Tartakovsky anticipates the new materials developed through this model will enhance supercapacitors, a type of next-generation energy storage that could substitute rechargeable batteries in high-tech devices like electric vehicles and cellphones. Supercapacitors integrate the best of what is presently available for energy storage – batteries, which store a lot of energy but charge slowly, and capacitors, which charge speedily but store little energy. The materials have to be able to endure both high energy and high power to avoid exploding, breaking, or catching fire.
Current batteries and other storage devices are a major bottleneck for transition to clean energy. There are many people working on this, but this is a new approach to looking at the problem.
Tartakovsky
The types of materials commonly used to build energy storage, known as nanoporous materials, appear solid to the human eye but have microscopic holes that provide them unique properties. Designing new, perhaps better nanoporous materials has, so far, been a matter of trial and error – positioning tiny grains of silica of varying sizes in a mold, filling the mold with a solid substance and then dissolving the grains to develop a material having several small holes. The technique requires a lot of planning, experimentation, labor, and modifications, without guaranteeing the final result will be the ideal 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. This framework also shows that if you arrange your grains like the model suggests, then you will get the maximum performance.
Tartakovsky
Beyond energy
Energy is just one industry that employs the use of nanoporous materials, and Tartakovsky said he believes this model will be relevant in other areas, as well.
This particular application is for electrical storage, but you could also use it for desalination, or any membrane purification. The framework allows you to handle different chemistry, so you could apply it to any porous materials that you design.
Tartakovsky
Tartakovsky’s mathematical modeling research spans urban development, medicine, neuroscience, and more. As a professor of energy resources engineering and an Earth scientist, he is an expert in the flow and transport of porous media, knowledge that is frequently underutilized in most disciplines, he said. Tartakovsky’s interest in enhancing battery design stemmed from partnership with a materials engineering team at the University of Nagasaki in Japan.
This Japanese collaborator of mine had never thought of talking to hydrologists. It’s not obvious unless you do equations – if you do equations, then you understand that these are similar problems.
Tartakovsky
The lead author of the study, “Optimal design of nanoporous materials for electrochemical devices,” is Xuan Zhang, Tartakovsky’s former PhD student at the University of California, San Diego. The Defense Advanced Research Projects Agency and the National Science Foundation supported the research.