3. RESULTS AND DISCUSSION
Scheme 1 displays the fabrication process of cellulose/CaCO3 membrane via a facile electrospinning method. CA is translated into cellulose by alkaline hydrolysis benefitting to improve the affinity with electrolytes.[29] The SEM images were used to record the micromorphology, and the corresponding results were shown in Figure 1 . It can be found that nano CaCO3 is spherical with a diameter of about 100 nm (Figure 1a ,). Nano CaCO3 is commonly used as plastic filler with toughening and reinforcing effects, also improving the thermal deformation temperature and dimensional stability of polymers.[30, 31] The morphologies of cellulose membrane and cellulose/CaCO3 membranes are shown in Figure 1b-d , these membranes show randomly arranged nanofibers and porous networks, which helps for liquid electrolyte uptake and fast migration of ions.[32, 33] As shown in Figure 1b, for cellulose membrane, the diameter of assembled fibers is uniform and the surface of fibers is smooth (Figure 1b ). After the introduction of nano CaCO3, the surface of cellulose/ CaCO3fibers becomes rougher and the diameter uniformity decreases accompanied by some humps after the addition of CaCO3. It is probably due to CaCO3 particles being encapsulated inside the fibers. These rough protrusions become more numerous as the amount of CaCO3 addition increases (Figure 1c and 1d ). Furthermore, the uniform distribution of Ca elements indicates that CaCO3 and polymer matrixes achieve compact and intact combination (Figure 1e ). Notably, the high magnification image in Figure 1f exhibits that nanoparticles are also coated on the fiber surface.