Large-Scale Nanofiber Manufacturing| Compressible PiezoelectricCeramicNanofiber Aerogels with Multifunction

Compressible Multifunctional Piezoelectric Ceramic Nanofiber Aerogels by Prof. Long Yunze (QDU), Prof. Zhang Jun (QDU), and Prof. Wu Hui (Tsinghua University)

Lead-free piezoelectric ceramics, as fundamental components of modern ceramic industries, are valued for their safety and environmental sustainability. Among them, barium titanate (BaTiO₃) ceramics, with excellent dielectric, ferroelectric, piezoelectric, and photoelectric properties, have garnered attention in electronics, energy, environment, catalysis, and medicine. However, the inherent brittleness of ceramic materials severely limits the widespread application of BaTiO₃, particularly in developing lightweight and flexible BaTiO₃ ceramic nanofiber aerogels, which remains highly challenging.

Recently, Prof. Long Yunze and Assoc. Prof. Zhang Jun from Qingdao University, along with Prof. Wu Hui from Tsinghua University, published their latest research, "Compressible Piezoelectric Ceramic Nanofiber Aerogels with Multifunction", in Advanced Fiber Materials. The team addressed the brittleness of BaTiO₃ nanofibers by employing an amorphous Al₂O₃ defect-repair strategy and optimized the solution blow spinning process through aerodynamic simulations, resulting in flexible and compressible BaTiO₃/Al₂O₃ ceramic nanofiber aerogels (BTAAs). These aerogels exhibit outstanding mechanical properties, including 11% tensile strain, 80% elastic compressive strain, and excellent fatigue resistance.

Moreover, BTAAs demonstrate superior performance in multiple applications: flexible electronics (piezoelectric response: 78 ms), thermal protection (thermal conductivity: 0.0275 W·m⁻¹·K⁻¹), sound absorption (noise reduction coefficient: 0.67), and high-temperature filtration (filtration efficiency: PM₀.₃ ≥ 99.96%). This work lays the foundation for large-scale production and broad application of flexible piezoelectric ceramic aerogels.

As shown in Figure 1, aerodynamic simulations optimized the stability of the turbulent field in solution blow spinning, reducing turbulence impact. This process directly yielded 3D-structured fiber sponge precursors, which were then calcined to produce lightweight (30 mg·cm⁻³), highly porous (98%), and flexible BTAAs. 

Figure 1: Spinning process optimization and BTAA fabrication

SEM revealed the nanofiber network and layered structure of BTAAs, attributed to turbulent diffusion along fiber layers. XRD and XPS confirmed tetragonal BaTiO₃ and amorphous Al₂O₃. The amorphous Al₂O₃ not only repaired defects from polymer decomposition but also inhibited BaTiO₃ grain growth, enhancing mechanical properties.

Figure 2: Material characterization of BTAAs

Tensile tests demonstrated significant improvement due to Al₂O₃'s flexibility and defect repair. Molecular dynamics simulations further elucidated the mechanism behind the enhanced mechanical performance, showing that amorphous viscous creep suppresses crystal slip, drastically improving fiber ductility.Thanks to their robust mechanics and layered structure, BTAAs exhibit exceptional deformability. Figure 3 highlights their compressibility, resilience, and fatigue resistance. 

Figure 3: Molecular dynamics simulations and compression tests.

Figure 4: Piezoelectric sensing and thermal insulation properties of BTAAs.

Figure 4 shows that BTAA-based piezoelectric devices respond rapidly to external stress (78 ms) and can monitor joint movements due to their flexibility. Structurally, BTAAs' porosity and layering yield low thermal conductivity (0.0275 W·m⁻¹·K⁻¹), outperforming most thermal insulation materials. Additionally, their electromechanical conversion capability synergizes with structural advantages for sound dissipation and electrostatic air filtration. Figure 5 reveals a high noise reduction coefficient (NRC: 0.67) and exceptional high-temperature filtration (PM₀.₃ ≥ 99.96%, pressure drop: 166 Pa), meeting standards for premium acoustic and filtration materials.Thus, BTAAs hold great potential in smart sensing, thermal protection, sound absorption, and air filtration.

Figure 5: Sound absorption and high-temperature filtration performance of BTAAs.

Paper link: https://link.springer.com/article/10.1007/s42765-025-00535-8