## 3 Results  
### Material Characterization  
The crystallographic phase of the synthesized Sb\({}_{2}\)O\({}_{3}\) was characterized by X-ray diffraction, and the XRD pattern is depicted in Figure 1a, in which all the strong and sharp peaks are consistent with standard pattern of the Orthorhombic Sb\({}_{2}\)O\({}_{3}\) phase (JCPDS card No. 71-0383), indicating the high crystalline Sb\({}_{2}\)O\({}_{3}\) was obtained. Figure 1b shows the SEM image of Sb\({}_{2}\)O\({}_{3}\), it is clear that this product is in cuboid-like shape with sizes of 200-400 nm in width and 0.6-2 um in length, and the cuboid particles easily aggregated together to form bigger particles. The HRTEM image of the as-prepared Sb\({}_{2}\)O\({}_{3}\) was exhibited in Figure 1c, the interplanar spacing is \(\sim\)3.15 A, this corresponds to the spacing between the (121) planes of Antimony Oxide. This is consistent with the X-ray diffraction pattern, as shown in Figure 1a.  
The Sb\({}_{2}\)O\({}_{3}\) sample was also characterized by Nitrogen adsorption-desorption isotherm measurement, and a typical IV-type isotherm was obtained, as shown in Figure 1d, indicating that there are nearly no micropores existing in the Sb\({}_{2}\)O\({}_{3}\) sample [43]. A large amount of mesopores (most diameters are less than 40 nm) could be observed in the pore-size distribution curve (inset in Figure 1d). Moreover, the hysteresis hoop of isotherms ascribes that the Sb\({}_{2}\)O\({}_{3}\) aggregated and formed a slit, consisting with SEM image of Sb\({}_{2}\)O\({}_{3}\) particles [44]. According to the BET equation and Barrett-Joyner-Halenda (BJH) Plot, the specific surface area of the Sb\({}_{2}\)O\({}_{3}\) sample was \(\sim\)3.42 m\({}^{2}\) g\({}^{-1}\).  
Figure 2a presents the formation process of cross-linking CMC-FA network by CMC and FA through the esterification reaction. A cross-linking CMC-FA network was formed via the condensation process of the hydroxyl group of CMC and carboxyl group of FA. To identify this chemical reaction, between CMC and FA, the FT-IR measurement was carried out (Figure 2b). For the FA spectrum, the hydroxyl bond dominates the range from 3700 to 2800 cm\({}^{-1}\), and the absorption band between 3200 and 2800 cm\({}^{-1}\) could be ascribed to hydroxyl bond between -COOH groups of FA [45]. By contrast, for the spectrum of CMC-FA, the nearly disappeared band between 3200 and 2800 cm\({}^{-1}\) indicates that the hydroxyl bond in carboxyl of FA was greatly weakened after the cross-linking reaction with CMC and \(\sim\)3400 cm\({}^{-1}\) has a broad peak which may be attributed to the residual hydroxyl bond of CMC. Moreover, the FT-IR spectra in Figure 2b showed that the C=O band in -COOH of FA shifted from 1677 cm\({}^{-1}\) to 1681 cm\({}^{-1}\), which could be ascribed to an ester group formed via cross linking during condensation reaction between FA and CMC [37]. This esterification reaction of the binders in the electrode could form a cross-linked polymeric network, which could increase the connection within the electrode (Sb\({}_{2}\)O\({}_{3}\), Super P, binder and Cu foil). At the same time, it provides an accommodation for the volume change of the Sb\({}_{2}\)O\({}_{3}\) electrode.  
Figure 1: Characterization of as-synthesized Sb\({}_{2}\)O\({}_{3}\) sample: (**a**) X-ray diffraction patterns; (**b**) scanning electron microscope image; (**c**) high-resolution transmission electron microscope image; (**d**) Nitrogen adsorption-desorption isothermal diagram and Barrett–Joyner–Halenda Plot (inset).