# Scalable Fabrication of Si-Graphene Composite as Anode for Li-ion Batteries
## 5 Conclusions  
We report a cost-effective and scalable method to fabricate Si-graphene nanocomposite as anode material for Li-ion batteries with high capacity and capacity retention performance. The fabrication procedure enables the uniform distribution of Si nanoparticles and graphene nanosheets in aqueous media by utilizing SDBS surfactants. The improved capacity retention of Si-graphene anode compared with Si anode is attributed to the mechanical flexibility of graphene that compromises the volume expansion of Si during the lithiation/delithiation process. The Si-graphene electrode showed an initial discharge capacity of 1307 mAh g\({}^{-1}\) at a current rate of 0.1C. At the 25 th cycle, the electrode retained a discharge capacity of 1270 mAh g\({}^{-1}\), with an excellent capacity retention of 97%. At the 50 th cycle, the electrode still retained high capacity retention of 89%. As a comparison, the pure Si anode possessed a higher initial discharge capacity (over 3000 mAh g\({}^{-1}\) at 0.1C), while the decay of the capacity retention was much faster, because Si nanoparticles experienced dramatic volume change during the charge/discharge process which ultimately led to limited cycle life. In addition, the electrochemical impedance performance further confirms the enhanced electrical conductivity and the denser SEI of the Si-graphene electrode. The reported fabrication approach is cost-effective and easy to scale up compared to \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Ref.** & **Anode Material** & **Synthesis Techniques/Conditions** & **Capacity Performance** \\ \hline \multirow{2}{*}{[21]} & \multirow{2}{*}{Si-graphene} & Aerosol spray process, atomize at 450 \({}^{\circ}\)C, & 890 mAh g\({}^{-1}\) at 5 A g\({}^{-1}\); \\  & & thermal annealing up to 800 \({}^{\circ}\)C, autoclave at & 81.9\% retention after \\  & & 650 \({}^{\circ}\)C, CVD at 900 \({}^{\circ}\)C, impurity wash off. & 150 cycles at 1 C (135 mA g\({}^{-1}\)). \\ \hline \multirow{2}{*}{[30]} & \multirow{2}{*}{Carbon-coated Si/graphene framework} & Synthesis of GO by m-Hummers method, hydrothermal reaction at 180 \({}^{\circ}\)C, freeze-drying, thermal treatment at 800 \({}^{\circ}\)C. & 830 mAh g\({}^{-1}\) at 1 A g\({}^{-1}\); \\  & & & hydrothermal reaction at 180 \({}^{\circ}\)C, freeze-drying, & 85.1\% retention after \\  & & & thermal treatment at 800 \({}^{\circ}\)C. & 200 cycles at 1 A g\({}^{-1}\). \\ \hline \multirow{2}{*}{[31]} & \multirow{2}{*}{Si/rGO/C} & Synthesis of GO by m-Hummers method, freeze-drying, CVD at 900 \({}^{\circ}\)C. & 894 mAh g\({}^{-1}\) at 1 C; \\  & & & freeze-drying, CVD at 900 \({}^{\circ}\)C. & 94\% retention after 300 cycles \\ \hline \multirow{2}{*}{[34]} & \multirow{2}{*}{Si-3D graphene} & Synthesis of GO by m-Hummers method, thermal reduction of SiO\({}_{2}\)/GO at 800 \({}^{\circ}\)C, synthesis of Si/3D graphene via molten-salt-assisted magnesium reduction at 700 \({}^{\circ}\)C, removal of unreacted SiO\({}_{2}\) using 5\% hydrofluoric acid. & 1307 mAh g\({}^{-1}\) at 0.1 C; \\  & & & 89\% retention after 50 cycles \\ \hline \multirow{2}{*}{This work} & \multirow{2}{*}{Si-graphene} & Surfactant-assisted ultrasonication, vacuum-assisted filtration & 1307 mAh g\({}^{-1}\) at 0.1 C; \\  & & & 89\% retention after 50 cycles \\ \cline{1-1}  & & & at 0.1 C (120 mA g\({}^{-1}\)). \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Synthesis and capacity performance of Si/graphene related anodes from literature. known techniques, making it a promising candidate for commercializing Si anode materials for LIBs. D.L. : Methodology, investigation, writing--original draft preparation; S.C., S.L., A.A.R. and M.M.M. : Methodology and investigation; H.Y., W.X. and T.L. : Writing--review and editing; supervision; H.H. : Writing--review and editing, conceptualization, supervision, funding acquisition. All authors have read and agreed to the published version of the manuscript. The authors appreciate the financial support from Army Research Lab, W911 NF 19-2-0329. Not applicable.