New capacitors are layered with 2D and 3D materials whose architecture promises higher energy and unprecedented efficiency.

A group of researchers from the McKelvey School of Engineering at Washington University in St. Louis, Missouri, have developed a new metamaterial designed to advance the capabilities of ferroelectric capacitors, a discovery that could open the door for the widespread adoption of this elusive electrical storage solution across many technologies.

Capacitors made from ferroelectric materials provide rapid charging and discharging capacity to a wide range of electronics. However, ferroelectric capacitors have historically suffered significant energy loss, making high-capacity energy storage difficult.

A ferroelectric design capable of increasing and controlling the amount of energy it holds has long been sought for its potential to dramatically boost efficiency in electronics.

A research team led by Sang-Hoon Bae, assistant professor of mechanical engineering at McKelvey, has had a breakthrough in overcoming these limitations, and the published study on their newly developed metamaterial architecture has proposed a method for controlling the physical properties governing how long it takes for charge to dissipate or decay.

A major breakthrough

The McKelvey research team devised a method that combines materials by stacking a 3D core between 2D layers precisely deposited with chemical and non-chemical bonds between each layer to create a stack that is roughly 30 nanometers thick.

The researchers produced one such structure with high energy density and low loss using two-layer molybdenum disulfide and barium titanate.

"We created a new structure based on the innovations we've already made in my lab involving 2D materials," Bae explained. "Initially, we weren't focused on energy storage, but during our exploration of material properties, we found a new physical phenomenon that we realized could be applied to energy storage, and that was both very interesting and potentially much more useful."

The layered sequences, called heterostructures, are precisely designed to balance between conductivity and non-conductivity to achieve optimal electric properties for energy storage. Bae and his colleagues have reported resulting energy densities up to 19 times higher than commercially available ferroelectric capacitors and an unprecedented efficiency of over 90%.

A new range of technologies

Tiny gaps in the material structure were all it took to adjust the properties of charge dissipation.

"That new physical phenomenon is something we hadn't seen before. It enables us to manipulate dielectric material in such a way that it doesn't polarize and lose charge capability," Bae explained. "We're not yet 100% optimal, but already we're outperforming what other labs are doing. Our next steps will be to make this material structure even better, so we can meet the need for ultrafast charging and discharging and very high energy densities in capacitors."

"We must be able to do that without losing storage capacity over repeated charges to see this material used broadly in large electronics, like electric vehicles, and other developing green technologies," Bae concluded.

This discovery has major promise of swift and efficient charging and discharging capabilities for various electronics industries, from personal electronics to power regulation for electric cars and infrastructure development.