fig8

Figure 8. (A) Unipolar P-E loops measured at different frequencies from 1 to 100 Hz at room temperature (RT) (20 °C) and 200 kV/cm, and (B) the corresponding W_rec, W_loss, and η values. (C) Unipolar P-E loops measured from RT to 160 °C at 10 Hz and 200 kV/cm, and (D) the corresponding W_rec, W_loss, and η values. (E) Contour map of the in situ Raman spectra collected from 20 to 200 °C. Enlarged three-dimensional Raman intensity maps in the ranges of (E1) 200 to 350 cm^-1 and (E2) 400 to 650 cm^-1. (F) Unipolar P-E loops measured after 1-10⁵ fatigue cycles at 10 Hz and 200 kV/cm, and (G) the corresponding W_rec, W_loss, and η values.