Researchers in the US have developed a process that could significantly boost the energy density of supercapacitors in personal electronic devices, wearable technology, and car audio systems.
By introducing isolated defects to a type of commercially available thin film ferroelectric in a straightforward post-processing step, a team led by researchers at the Department of Energy's (DOE) Lawrence Berkeley National Laboratory (Berkeley Lab) has demonstrated that a common material can be processed into a top-performing energy storage material.
The research is supported by the Materials Project, an open-access online database that virtually delivers the largest collection of materials properties to scientists around the globe. Today, the Materials Project combines both computational and experimental efforts to, among other goals, accelerate the design of new functional materials. This includes understanding ways to manipulate known materials in ways that improve their performance.
The material is based on a so-called "relaxor ferroelectric," a ceramic material that undergoes a rapid mechanical or electronic response to an external electric field and is commonly used as a capacitor in applications like ultrasonics, pressure sensors, and voltage generators.
The applied field drives changes in the orientation of the electrons in the material. At the same time, the field drives a change in the energy stored in the materials, making them a good candidate for use beyond a small-scale capacitor. The problem to solve is how to optimize the ferroelectric so that it can be charged to high voltages and discharged very rapidly without damage.Introducing the local defects allowed it to withstand bigger voltages safely.
"You've probably experienced relaxor ferroelectrics on a gas grill. The button that lights the grill operates a spring-loaded hammer that smacks a piezoelectric crystal, which is a type of relaxor, and creates a voltage that ignites the gas," said Lane Martin, a faculty scientist in the Materials Sciences Division (MSD) at Berkeley Lab and professor of materials science and engineering at the University of California, Berkeley. "We've demonstrated that