Customizing Three-Dimensional Elastic Barium Titanate Sponge for Intelligent Piezoelectric Sensing

Area of Science:

• Materials Science
• Nanotechnology
• Energy Harvesting

Background:

• Porous piezoelectric energy harvesters (PEHs) offer high efficiency due to excellent compression recovery.
• Conventional methods are limited to bulk PEHs, hindering the creation of complex 3D structures for improved performance.
• Need for advanced fabrication techniques to create tailored 3D piezoelectric structures.

Purpose of the Study:

• To develop a novel composite ink for 3D printing of piezoelectric sponges.
• To enable the fabrication of functional 3D piezoelectric structures with customized designs.
• To enhance the performance of piezoelectric energy harvesters and explore their application in intelligent sensing.

Main Methods:

• Invented a composite ink comprising waterborne polyurethane (WPU), barium titanate (BTO), and cellulose nanofibers (CNFs).
• Utilized direct ink writing (DIW) 3D printing combined with freeze-drying to create customized piezoelectric sponges.
• Fabricated and tested a lattice sponge structure and a 'boomerang' configuration for anisotropic bending sensing.

Main Results:

• The printed lattice sponge demonstrated remarkable compression recovery (70%) and high relative sensitivity (9.83 mV/kPa*wt %).
• Achieved a broad operating pressure range (2.98-37 kPa), significantly wider than existing BTO or PZT sensors.
• Successfully demonstrated a 3D piezoelectric sponge as an anisotropic bending sensor for monitoring sports posture.

Conclusions:

• A versatile DIW 3D printing strategy was established for fabricating elastic sponges with high piezoelectricity.
• Customizable 3D PEH structures can significantly enhance energy conversion efficiency and sensing capabilities.
• This approach offers a promising pathway for developing flexible, self-powered intelligent sensing systems.