Supersonically Sprayed Cobalt Titanate and PVDF for Flexible Piezoelectric Nanogenerators

Piezoelectric nanogenerators (PENGs) are the core components of self-powered devices used in sensors, ecofriendly wearable gadgets, and biomedical implants. This study introduces and demonstrates a flexible PENG with supersonically cold-sprayed films of cobalt titanate (CTO) and polyvinylidene fluoride (PVDF). An electrically poled PENG produces a maximum output voltage of 34.8 V under a tapping force of 20 N, whereas a CTO/PVDF-based PENG exhibits 25.4 V across a loading resistance (RL) of 50 M omega and generates a short-circuit current of 30 mu A at 0.1 M omega. Furthermore, the maximum power density is 25 mu W center dot cm-2 at RL=0.6 M omega. Cyclic tapping and bending test results show that open-circuit voltages (Voc) of 25.4 and 5.8 V are produced under the tapping cycle of Ntap=4200 and bending cycle of Nbend=750, respectively, confirming the mechanical durability of the PENG. Thus, the potential of CTO/PVDF films for use in PENGs with various functionalities can be confirmed based on the Voc values generated from bending, mobile tapping, walking, and lifting movements.

Automated summary

This study presents a flexible PENG with supersonically cold-sprayed films of cobalt titanate and polyvinylidene fluoride. The PENG exhibits excellent mechanical durability and generates high voltage and current output during tapping and bending tests.