fig4

Figure 4. The energy storage performance of flexible BTO/STO-BFO SPE film on mica substrate. (A) The P-E loops of flexible BTO/STO-BFO SPE film under different E, and the local grey area have been magnified; (B) The W_rec and η of flexible BTO/STO-BFO SPE film with different E; (C-H) The P-E loops and energy storage performance of flexible BTO/STO-BFO SPE film under (C and D) different temperature, (E and F) bending radii and (G and H) bending cycle. BTO: Barium titanate; STO: strontium titanate; BFO: bismuth ferrite; SPE: superparaelectric; P-E: polarization-electric field; E: electric field; W_rec: recoverable energy density; η: energy storage efficiency.