A green-synthetic spiderweb-like Si@Graphene-oxide anode material with multifunctional citric acid binder for high energy-density Li-ion batteries

Silicon (Si) is considered to be one of the alternative anode candidates for lithium-ion batteries due to the high theoretical capacity. Enhancing the columbic efficiency, cycle stability, alleviating the pulverization and decreasing the manufacturing cost are the major challenges that procrastinate the commercialization of Si anode. Inspirited by spiderweb structure, the Si nanoparticles (SiNPs) was encapsulated by the multifunctional binder citric acid (CA) which can effectively prevent the continuous formation of solid electrolyte interphase (SEI) film. Similar to the spiders, the SiNPs@CA particles anchors on the graphene oxide (GO) sheets through chemical bond which inhibit the irreversible sliding of SiNPs and maintain a stable and tough structure of electrode during the charge/discharge process. Therefore, this SiNPs@CA@GO anode retains a capacity of 2566 mAh g⁻¹ after 100 cycles at a current density of 1 A g⁻¹ with a superb initial coulombic efficiency of 81%. In addition, the Li⁺ diffusion coefficient of the composite was calculated to be 10⁻⁸-10⁻¹⁰ cm² s⁻¹ by EIS and GITT methods, which further demonstrates the excellent electrochemical performance of the composite. Thus, the low-temperature and easily scaled-up fabrication technique with robust non-toxic binder system enables this SiNPs@CA@GO anode suitable for commercial application.