Cella Energy partners with NASA Kennedy Space Center to develop its solid-state micro-bead hydrogen storage technology
Hydrogen storage start-up Cella Energy’s US subsidiary has signed a contract with NASA Kennedy Space Center (KSC) for the further research, development and potential production of its micro-bead, polymer-encapsulated chemical hydride technology. (Earlier post.) Cella already has offices in the Space Life Sciences Laboratory at Kennedy and is expected to become an early tenant at Exploration Park, a research center now under construction at the space center.
KSC’s obligation under the agreement is to serve as a consultant to Cella for developing an integrated solution for hydrogen storage and help Cella incorporate Kennedy-developed hydrogen-sensing color-changing polymers. Cella also is interested in working with lightweight aerofoam and aeroplastic, another innovation of NASA’s, notable for their thermal insulating properties.
We have a lot of great capabilities at Kennedy and some exceptional talent in both our materials and cryogenics labs and I think that’s what mostly attracted them to us.—Robert Hubbard, Partnership Development manager at Kennedy
Cella Energy, a spin-off company from the Rutherford Appleton Laboratory in the UK, is seeking to develop and to commercialize a way to nanostructure and encapsulate complex chemical hydride materials to improve their performance, in terms of temperature of operation, adsorption and desorption kinetics, and to render them safe to handle in air.
Cella Energy has developed a method using a low-cost coaxial electrospinning or electrospraying process. This traps a complex chemical hydride inside a nano-porous polymer, speeds up the kinetics of hydrogen desorption, reduces the temperature at which the desorption occurs and filters out many if not all of the damaging chemicals. It also protects the hydrides from oxygen and water—making it possible to handle in air.
The coaxial electrospinning process can be used to create micron-scale micro-fibres or micro-beads nano-porous polymers filled with the chemical hydride.
Cella’s current composite material uses ammonia borane (NH3BH3) as the hydride and polystyrene as the polymer nano-scaffold. Ammonia borane in its normal state releases 12 wt% of hydrogen at temperatures between 110 °C and 150 °C, but with very slow kinetics. In the Cella materials, the accessible hydrogen content currently is reduced to 6 wt% but the temperature of operation is reduced so that it starts releasing hydrogen below 80 °C and the kinetics are an order of magnitude faster, according to th company.
Although suitable for proof-of-concept work and potentially for initial demonstrator projects, the current microbeads are not commercially viable, Cella says. They are expensive to make and cannot be easily re-hydrided.
Cella is working on other hydride materials with slightly lower hydrogen contents but with the ability to cycle them into the hydride phase many hundreds of times. These are being encapsulated in hydrogen- permeable high-temperature polymers based on polyimide.
The eventual goal is to use the pellets in fuel cells.