The Raman shift and X-ray diffraction
pattern indicate that the BaTiO 3 NPs have good crystallinity
with an excellent ferroelectric tetragonal phase. The MW-CNTs
(Carbon Nano-material Tech. Co.), which are prepared via catalyst
chemical vapor deposition, have a diameter of 5 to 20 nm
and a length of ∼ 10 μ m (see TEM images of Figure S1b-i). We
also employed the SW-CNTs with a diameter of ∼ 3 nm and
RGO obtained by modifi ed Hummers methods [ 25 ] (see Method
S2) to confi rm the universality of carbon nanomaterials in
energy generation behavior (see Figures S1c and S1d). The photograph
in Figure 1 f shows the core p-NC material stretched by