## 3 Results and Discussion
The nano-sized active materials affect the electrochemical stability in view of available surface area and shortening the Li-ion diffusion path; all of these factors are contributed to observed cyclability [40; 41]. Moreover, the amorphous carbon matrix can stabilize Si volume change and offer the diffusion path of lithium ions toward the active Si phase during the Li-alloying/dealloying process. It has been reported that carbon is beneficial to not only buffer the volume changes during the cycling process, but also to avoid agglomeration of the silicon particles [42]. We have further compared our results with other reported Si/C based anode materials. Among them, our material shows good capacity retention and high reversible capacity values even after 100 th cycle at 1 C rate (Table 2). Figure 3: Electrochemical characteristics of the coin-type half cells produced by 8 h milled Si/C nanocomposite powders: (**a**) potential vs. lithiation/delithiation curves; (**b**) discharge capacity and coulombic efficiency; and (**c**) differential capacity plot for 1 st, 3 rd, and 20 th cycle. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Sample Name** & \begin{tabular}{c} **Weight Ratio of Active** \\ **Material in Electrode** \\ \end{tabular} & **1 st Discharge Capacity** & \begin{tabular}{c} **1 st Coulombic** \\ **Efficiency** \\ \end{tabular} & **Cyclic Stability** & \
\begin{tabular}{c} **Capacity** \\ **Retention** \\ \end{tabular} & **Ref.** \\ \hline Si/C nanocomposite & 80\% & 1658 mAh/g (at 0.1C) & 77.5\% & 1181 mAh/g (at 1 C) after 100 cycles & 71.2\% at 100 th cycle & In this work \\ \hline Si/graphite & 80\% & 1533 mAh/g (at 0.2 A/g) & 72.4\% & 665 mAh/g (at 0.2 A/g) after 100 cycles & 43.3\% at 100 th cycle & [18] \\ \hline Si/C composite & 80\% & 1387 mAh/g (at 0.2 A/g) & 82.5\% & 678 mAh/g (at 0.2 A A/g) & 49.2\% at 100 th cycle & [18] \\ \hline Si/C composite & 80\% & 2600 mAh/g (at 0.1 A/g) & 71\% & 1120 mAh/g (at 0.1 A/g) & 43\% at 100 th cycle & [42] \\ \hline Si/C nanocomposite & 80\% &
\begin{tabular}{c} 1561 mAh/g (at 0.15 \\ mA/cm\({}^{2}\)) \\ \end{tabular} & 61.9\% & 626 mAh/g (at 0.15 mA/cm\({}^{2}\)) after 30 cycles & 40.1\% at 30 th cycle & [43] \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Electrochemical performance of the Silicon/Carbon based anode materials for Li-ion secondary batteries (capacity retention for 100 th cycle was calculated based on the first cycle reversible capacity). The differential capacity plots (DCPs) during the 1 st, 3 rd, and 20 th cycles of the Si/C nanocomposite electrodes are shown in Figure 3c. The intense peak observed at 0.067 V of the first cycle corresponds to the lithiation of crystalline Si to form an amorphous Li\({}_{x}\)Si alloy [44; 45]. In the case of third cycle, two peaks were observed at 0.06 V and 0.2 V belonging to the phase transition process of the Li\({}_{x}\)Si. A single peak observed at 0.087 V in the higher order cycles, i.e., 20 th cycle, represent a stable SEI formation and constant lithiation or alloying process of the amorphous Si with Li. The pure Si exhibits a peak at 0.45 V, indicating the de-alloying of lithium during the first cycle discharge [46]. Beyond the first cycle, two broad peaks at 0.52 and 0.55 V during the delithiation process were observed. The two broad peaks indicate the conversion of crystalline silicon to an amorphous state after the first cycle. [PERSON] et al. and [PERSON] et al. reported that the peaks obtained at high-voltage delithiation (0.35-0.5 V) are attributed to the amorphous Li-Si alloys and the formation of amorphous silicon [47; 48]. In addition, [PERSON] et al. reported that the lithiation peak observed at 0.05 V after the first cycle ascribed to crystallization of the Li\({}_{3.75}\)Si phase [49]. However, in the case of extended cycles at 20 th cycle, the peak appeared at 0.1 V due to the amorphization process of Si during the initial cycles.