Image of two-dimensional nanomaterial flakes
Layered, two-dimensional nanomaterial flakes are among the materials that scientists project will revolutionize energy storage devices and enable widespread use of renewable energy resources.

The challenge of building an energy future that preserves and improves the planet is a massive undertaking. Scientists and politicians have recognized the need for an urgent and sizable shift in the world’s mechanisms of energy production and. A course correction of this magnitude is certainly daunting, but a new report in the journal Science suggests that the technological path to achieving sustainability has already been paved.

“Most of the biggest problems facing the push for sustainability can all be tied back to the need for better energy storage,” said Yury Gogotsi, PhD, Distinguished University and Bach professor at Drexel University’s College of Engineering and lead author of the paper. “Whether it’s a wider use of renewable energy sources, stabilizing the electric grid, managing the energy demands of our ubiquitous smart and connected technology or transitioning our transportation toward electricity — the question we face is how to improve the technology of storing and disbursing energy. After decades of research and development, the answer to that question may be offered by nanomaterials.”

Most plans for energy sustainability assert the need to reign in energy consumption while also tapping into new renewable sources, like solar and wind power. The problem with integrating renewable resources into our energy grid is that it’s difficult to manage energy supply and demand given the unpredictable nature of...nature. So, massive energy storage devices are necessary to accommodate all the energy that is generated when the sun is shining, and the wind is blowing, and then be able to disburse it quickly during high energy-use periods.

Unstopping the energy-storage logjam has been a concerted goal for scientists who apply engineering principles to creating and manipulating materials at the atomic level. Their efforts in the last decade alone have already improved the batteries that power smartphones, laptops and electric cars.

“Many of our greatest achievements in energy storage in recent years are thanks to the integration of nanomaterials,” Gogotsi said. “Lithium-ion batteries already use carbon nanotubes as conductive additives in battery electrodes to make them charge faster and last longer. And an increasing number of batteries use nano-silicon particles in their anodes for increasing the amount of energy stored. Introduction of nanomaterials is a gradual process and we will see more and more nanoscale materials inside the batteries in the future.”

Battery design, for a long time, has been based primarily on finding progressively better energy materials and combining them to store more electrons. But, more recently, technological developments have allowed scientists to design the materials of energy storage devices to better serve these transmission and storage functions.

This process, called nanostructuring, introduces particles, tubes, flakes and stacks of nanoscale materials as the new components of batteries, capacitors, and supercapacitors. Their shape and atomic structure can speed the flow of electrons. And their ample surface area provides more resting places for the charged particles.

The effectiveness of nanomaterials has even allowed scientists to rethink the basic design of the batteries themselves. With metallically conducting nanostructured materials ensuring that electrons can freely flow during charge and discharge, batteries can lose a good bit of weight and size by eliminating the metal foil current collectors that are necessary in conventional batteries. As a result, their form will no longer be a limiting factor for the devices they’re powering.

Batteries are getting smaller, charging faster, lasting longer and wearing out more slowly — but they can also be massive, charge progressively, store huge amounts of energy for long periods of time, and distribute it on demand.

“It is a very exciting time to work in the area of nanoscale energy storage materials,” said Ekaterina Pomerantseva, PhD, associate professor in the College of Engineering and coauthor of the paper. “We now have more nanoparticles available than ever — and with different compositions, shapes and well-known properties. These nanoparticles are just like Lego blocks, and they need to be put together in a smart way to produce an innovative structure with performance superior to any existing energy storage device. What makes this task even more captivating is the fact that unlike Legos, it is not always clear how different nanoparticles can be combined to create stable architectures. And as these desired nanoscale architectures become more and more advanced, this task becomes more and more challenging, triggering the critical thinking and creativity of scientists.”

Gogotsi and his coauthors suggest that capitalizing on the promise of nanomaterials will require some manufacturing processes to be updated and continued research on how to ensure the materials’ stability as their size is scaled up.

“The cost of nanomaterials compared to conventional materials is a major obstacle, and low-cost and large-scale manufacturing techniques are needed,” Gogotsi said. “But this has already been accomplished for carbon nanotubes with hundreds of tons being manufactured for the needs of the battery industry in China. Preprocessing the nanomaterials in this way would allow the use of current battery manufacturing equipment.”

They also note that the use of nanomaterials would eliminate the need for certain toxic materials that have been key components in batteries. But they also suggest establishing environmental standards for future development of nanomaterials.

“Whenever scientists consider new materials for energy storage, they should always take into account toxicity to humans and the environment, also in case of accidental fire, incineration, or dumping into waste,” Gogotsi said.

What this all means, according to the authors, is that nanotechnology is making energy storage versatile enough to evolve with the shift in energy sourcing that forward-looking policies are calling for.

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