Polysiloxane is an environmental friendly chemical that is used in adhesives, medicine, and insulations, respectively. Currently, the solid electrolyte interphase (SEI) formation on cathode and anode in lithium ion battery is important due to the ionic diffusivity enhancement and lowers the irreversibility of electrochemical reaction. Silicon is regarded as one of the most promising anodes for lithium ion battery owing to its large theoretical energy density (about 4200 mAh g⁻¹). However, its practical application is limited by structure degradation.

In this study, a new compound has been developed, which is combined with the functions of SEI formation and particle adhesion in electrode. This new technology is used to eliminate the huge irreversible reaction on first cycle and effectively extend the cycle life. The new compound was composed by the bismaleimide (BMI) and the polymethylhydrosiloxane (PMHS) through hydrosilylation reaction (shown in Figure 1). The functionalized aqueous product provides three performances including excellent adhesion property with silicon particles on backbone structure, high ionic conductive SEI with high reduction potential on imide structure, and ionic hopping site on acrylate ethyl oxide side chain.

It is the first time that combines binder, SEI, and ionic transfer functions in one material in order to solve the uneven distribution of electrochemical reaction on silicon particles. In addition, we anticipate that the volume expansion and irreversible reaction on silicon can be effectively eliminated by this new technology. We also expect that this functionalized smart aqueous binder delivers outstanding electrochemical behavior and are looking forward to eradicate the disadvantages of silicon.