Figure 6. (a) Cycling performance and (b) Energy density in the 80th cycle.
The battery performance of four samples, including 100GR, baseline, CM30, and EM4C (Table 2 ) is shown in Figure 6 . Overall, the discharged capacity of all samples decreases after testing time. Indeed, the 100GR sample drops dramatically in discharge capacity, from 140.27 to 51.35 mAh.g-1 (Figure 6 a). Meanwhile, the battery performance increase when using the pre-lithiation method. In detail, the CM30 and EM4C show the capacity of 99.08 and 137.06 mAh.g-1 in the first cycle, respectively, which is increased around 2-3 times compared to the baseline sample. Therefore, the energy density of the EM4C is much higher than the others, which is 98.68 mWh.g-1. As a result, the EM method effectively enhanced the battery performance.