## 3 Results and Discussion
### Electrochemical Studies
Following the VH mode, the self-discharge test was completed in the OCP mode. The SD of the SC device is directly related to the Faradic charge reaction as well as the resistance/diffusion charge redistribution [59]. After four consecutive cycles of the voltage holding procedure, the leakage currents of the INS1 (60 uA, 42 uA, 38 uA, 37 uA) indicate that there was no formation of internal resistance during the voltage-holding procedure. At OCP, the self-discharging (SD) of INS-based devices decreased gradually from 1.0 V to 0.8 V, whereas the SC devices remained stable at 0.8 V. Correspondingly, the self-discharge mechanism is related to how the SSC cell behaves as it self-discharges after being charged to a specific potential [42; 60]. Active-controlled Faradaic reactions, resistance-limited redistribution, and diffusion-limited redistribution of charge are all potential outcomes, as are activated-controlled faradaic processes and charge redistribution alone [57]. The self-discharge must be repeated several times for the activation control model to be valid [59]. Another possibility is that other mechanisms are involved in the charge transmission process, as indicated by the variation in self-discharge. It followed the same path for four successive charge-discharge cycles, the voltage holds, and self-discharges. Samples from INS0 to INS5 were tested for SD, VH, and leakage currents, denoting that SD mitigation was attributable to an increase in nanostructural integrity. Figure 6i,j show the morphology demonstration of samples INS0 and INS5 before and after 10,000 cycle stability tests. In order to aid in comprehension, structural change is indicated in the scheme in both illustrations. After 10,000 cycles, the petal structure of sample INS0 is lumped and aggregated. Furthermore, the granules can still be seen in the image taken after the cycle in Figure 6i. In INS5 (which shows some swelling in the structure), there is no significant difference, indicating improved material  
Figure 6: (**a**–**d**) GCD (100 cycles) + VHT (2 h) + SD (2 h), (**e**–**h**) leakage current during voltage holding. (i,j) FESEM images test of INS0 and INS5 before and after 10,000 cycle stability tests. physical structure stability. Structural stability is extremely high for the reinforced structure represented in Figure 6j. Table 3 shows that the cyclic stability and capacitance values of our work are higher/comparable to those of several indium-based electrode materials that were previously reported. The developed SSC device was demonstrated to be capable of providing additional power for wireless communication to validate its practical application. Supplied power from WPT was used for the SSC charging and PPG/BLE module operation, respectively. In this instance, it allows for the realization of a fully battery-free system. Figure 7a depicts a schematic cartoon of the wireless powered BLE/PPG module including the SSC. Typically, wearable devices for health care are designed as two-part, (1) measuring biosignals with low power consumption; (2) sending data to other platforms (e.g., smartphone, desktop, server) with momentary high-power consumption [71; 72; 73]. The wireless powered system with temporary energy storage such as SCs is preferable for the health care devices rather than chemical batteries because of its long-lasting potential safety and maintenance issue. The device efficiency is further improved by using a simple domestic vacuum sealing method, making it suitable for long-term environmental stability.