Researchers at NASA’s Marshall Space Flight Center have developed a new dielectric material based on barium titanate nanopowder processed via spark plasma sintering (SPS). The rapid and full densification achieved by SPS, together with a unique ceramic nanopowder processing approach, enables new ceramic materials with extremely high relative permittivity or dielectric constant.
New energy storage devices that can replace standard electrochemical batteries or ultracapacitors and that can offer major gains in performance, weight, reliability, and safety are critical. This new technology offers a potential solution and can also offer significant advantages for many other non-space applications that use batteries or supercapacitors.
Barium titanate ceramics have been used as a capacitor material for many years and are the mainstay for millions of chip capacitors used in systems today. The research behind the NASA Spark Plasma Sintered Dielectric Technology was focused on optimizing the ferroelectric characteristics of barium titanate to expand its capabilities as an energy storage/device material.
Initial research efforts resulted in a prior closely related NASA innovation — Solid-State Ultracapacitor for Improved Energy Storage — whereby the innovators developed a technology for close control of the polycrystalline microstructure and grain boundary composition of the novel barium titanate material. The current innovation builds on that work with the demonstration of the use of SPS as an additional component to providing a novel and unique composition and nanoscale microstructure. The current work began as a collaborative effort with Oak Ridge National Laboratory to evaluate SPS as an alternate method to densify the green nanopowder compact.
Tests of the spark plasma sintered barium titanate materials have demonstrated gigantic permittivities and very low dielectric losses. The NASA innovators continue to optimize the materials and processes to further understand and improve energy storage density of the material.