Effects of binders on electrochemical properties of high capacity silicon composite anodes

In this study, the effects of four kinds of binders including polyimide (PI), sodium alginate (SA), polyvinylidene fluoride (PVDF), and sodium carboxymethyl cellulose (CMC) on the electrochemical properties of a high capacity silicon composite anode (SMG@C) were investigated. Phase constitutes and morphologies of the SMG@C anode materials were carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The electrochemical properties of the SMG@C anode using the four kinds of binders were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results showed that in the case of using SA as the binder, the discharge capacity reached 1207 mAh/g after 75 cycles at a current density of 100 mA/g, indicating the best cycle stability. Moreover, the discharge capacity can be restored to the initial capacity state during rate-cycle testing; and the impedance was the lowest among the four binders. This paper also analysed the measured electrochemical impedance spectra with the four different binders and revealed their action mechanisms.