Mechanically robust and hierarchically porous CNC-reinforced electrospun cryogel for triboelectric energy harvesting and air filtration

초록

The development of multifunctional materials capable of both mechanical energy harvesting and environmental remediation remains a significant challenge in sustainable technology. Here, we report mechanically robust and hierarchically porous cellulose nanocrystal (CNC)-reinforced electrospun cryogels fabricated by electrospinning followed by aqueous dispersion and freeze-drying of polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), silica particles (SiO2), and CNCs. The resulting CNC/PAN-PVDF-SiO2 (CPPS) cryogel exhibits an ultralow density (approximate to 0.084 g cm-3), high mechanical robustness, and a hierarchically porous nanofiber network. When incorporated as a triboelectric nanogenerator (TENG), CPPS cryogels generate output voltages up to 180.2 V, currents of 8.4 mu A, and charge densities of 52.9 mu C m-2, achieving 2-3 times higher performance than CNC-cryogel, owing to the synergistic effects of SiO2-mediated charge trapping, PVDF dipolar polarization, and hierarchical porosity. The device maintained stable output over 18,000 cycles. Furthermore, it achieves a power density of 977 mW m-2, sufficient to drive small electronic devices. In air filtration tests, CPPS achieves a high PM2.5 capture efficiency (98.9%) and a quality factor (0.083 Pa-1). This mechanically robust and hierarchically porous CNCreinforced electrospun cryogel platform demonstrates versatility in both energy harvesting and air purification applications, offering new opportunities for sustainable environmental monitoring systems and portable purification devices.

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