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 (LiNbO3), possess superior electro-physical properties yet remain underutilized in triboelectric applications. This study demonstrates the potential of LiNbO3 crystals in coupled Pyroelectric-LiNbO3 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 Vp-p) and a 700 % rise in current (∼15.2 µA) compared to fluoropolymer-based TENGs (∼215 Vp-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 LiNbO3 for sustainable energy and sensor technologies.<p></p>