Piezoelectric Effect in PENG: Opposite Phase Electric Signals with Electrode Polarity

According to the theory of piezoelectricity, it can be concluded that when a piezoelectric device is subjected to force, the electric signals generated will have opposite phases depending on the polarity of the electrodes connected to the testing equipment. This characteristic is reflected in the electrical signal output features shown in Figure 3e-f and Figure S10. In-depth analysis of optimizing the addition of different mass ratios to PVDF's A-titanium dioxide, AR-titanium dioxide, and R-titanium dioxide is presented in Figure S11-13. Both forward and reverse connection tests demonstrate that the electric signals generated have opposite phases, indicating that the detected output is produced by the piezoelectric effect of the piezoelectric film in the PENG.