Realizing the potential of polyethylene oxide as new positive tribo-material: Over 40 W/m2 high power flat surface triboelectric nanogenerators

The on-going research into the negative tribo-materials has led to significant improvements in the performance of triboelectric nanogenerators (TENGs), however, very little attention has been paid to the positive tribo-materials. This work reports on the use of poly(ethylene oxide) (PEO) as the positive tribo-material for the fabrication of TENGs and shows that PEO has much higher positive tribo-polarity than the existing choice of polyamide-6 (PA6). A 2 × 2 cm² TENG comprising of spin-coated flat PEO and polydimethylsiloxane (PDMS) films produces a voltage of up to 970 V, a current density of 85 mAm⁻², and a power of ~ 40 W m⁻² under a 50 N contact force. Comparatively, the PA6/PDMS TENG only produces 630 V, 30 mAm⁻², and a power of ~ 18 W m⁻², showing the remarkable property of the PEO as the positive tribo-material. The results are further supported by the contact potential difference between PEO (1.26 V) and PA6 (0.87 V) obtained using Kelvin Probe Force Microscopy. Furthermore, the triboelectric behavior of PEO is explained in the context of the positively charged oxygen functional groups and the lower work function of PEO as compared to PA6. The work thus expands the current portfolio of materials used for triboelectric nanogenerators with great prospects.