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%.