The Naval Undersea Warfare Center Division Newport has developed and tested a patent pending platform technology to apply small levels of compressive stress to domain engineered PIN-PNM-PT ferroelectric single crystals. The pre-stress brings the crystal near the phase transition so only a small thermal or mechanical input is required to drive the crystal back and forth through the phase transformation. The transformation yields a large change in polarization and strain leading to energy density per cycle nearly two orders of magnitude greater than linear piezo materials.
The Navy’s technology exhibits relatively uniform operation over a broad bandwidth, unlike conventional mass spring oscillatory harvesters that are limited to peak performance near a resonant frequency. The devices are also tunable—changing the stress level on the crystal alters the threshold at which phase transition will occur, leading to broader ranges where waste heat or other input sources could be exploited.
- Compact: High energy density per cycle (see chart) enables significantly smaller devices or more performance from an existing form factor
- Superior Bandwidth: Not limited by resonant frequencies; operates across a range of thermal and mechanical regimes
- Tunable: Adjusting the pre-stress applied to the crystal alters the phase transition point so the device can operate at optimal temperature, electric, magnetic, and mechanical trigger points
- Pending US patent application
- Potential for collaboration with Naval Undersea Warfare Center Division Newport researchers