Why not inorganic ferroelectrics: Harnessing the pyroelectric charges for triboelectric nanogenerators

Multifunctional, ferroelectric fluoropolymers are regarded as the de facto materials for triboelectric nanogenerators. However, their comparatively low polarisation, dielectric constants, and pyroelectric coefficients result in sub-optimal pyroelectric-triboelectric coupling. In contrast, inorganic ferroelectrics, such as lithium niobate (LiNbO 3 ), possess superior electro-physical properties yet remain underutilized in triboelectric applications. This study demonstrates the potential of LiNbO 3 crystals in coupled Pyroelectric-LiNbO 3 Triboelectric Nanogenerators (PL-TENGs) for harvesting waste, low-grade heat and temperature monitoring. Under a 0.11 K.s -1 temperature gradient, the PL-TENG exhibits a 330% increase in output voltage (~720 V p-p ) and a 700% rise in current (~15.2 µA) compared to fluoropolymer-based TENGs (~215 V p-p and ~1.3 µA). This performance advantage is sustained at higher temperatures, with voltage and current increasing by 285% and 395%, respectively, at 353 K compared to 313 K. High voltage Kelvin probe force microscopy reveals a rapid surface potential inversion (+72.6 V to -28.7 V) for a 1 K temperature change, corresponding to a pyroelectric coefficient of -53.4 µC.m −2 .K -1 , validated by in-situ X-ray photoelectron spectroscopy. The increased exchange of pyroelectric effect-induced screening charges amplifies the triboelectric activity, enhancing efficient low-grade heat sensitivity and harvesting. This work underscores the promise of inorganic ferroelectrics like LiNbO 3 for sustainable energy and sensor technologies. The work demonstrates the exceptional coupling of pyro-triboelectric effect in inorganic ferroelectrics for developing Pyroelectric LiNbO 3 Triboelectric Nanogenerators (PL-TENGs). Leveraging pyroelectric effect-induced screening charges, the PL-TENGs achieve a 330% increase in output voltage and a 700% rise in current under small temperature gradients, with robust performance even at elevated temperatures, significantly outperforming the conventional fluoropolymer-based triboelectric nanogenerators. • Inorganic LiNbO 3 provides temperature-modulated triboelectric response • 1 K temperature difference causes rapid surface potential inversion (+72.6 V to -28.7 V) • Pyroelectric coeff. -53.4 µCm⁻²K⁻¹, measured via in-situ photoelectron spectroscopy • LiNbO 3 pyroelectric harvesters show 330% higher voltage (~720 V) and 700% more current (~15 µA) than PVDF