Figure 7. Electrochemical properties of PCNTs-6//ZMOP-4 ZISCs: (a) schematic diagram; (b) CV curves of Zn//ZnxMnO2 and Zn//PCNTs-6 at 1 mV s-1; (c) CV curves of PCNTs-6//ZMOP-4 at different sweep speeds; (d) GCD curves of PCNTs-6//ZMOP-4 at different current densities; (e) specific capacitance curves with different positive and negative mass ratios; (f) energy-power density diagram; (g) GCD curves for the first 10 turns and GCD curves for the last 10 turns; (h) Zn//ZMOP-4 /PCNTs-6 cycle performance of 5000 cycles at 0.2 Ag-1.
Figure 7e records the impact of different mass ratios of electrodes on the specific capacitance of assembled ZISCs. It can be seen that the different quality ratio is relatively small to the capacitance at various current densities. However, when the positive and negative quantity ratio of 2:1.9 mg, ZISCs can attain higher specific capacitance and stability. In Figure 7f , the ZISCs have an energy density of 37 Wh kg-1 at a power density of 64 W kg-1. Meanwhile, when the power density is increases to 0.867 kW kg-1, the energy density still maintained at 20 Wh kg-1. Figure 7g reflects the GCD curve of 10 cycles before and after the cycle. Figure 7h shows that after 5000 cycles at 0.2 A g-1, the device displays extraordinary cycle performance, with capacity retention of 86.36% and coulomb efficiency of 99.32%.