Pseudocapacitive performance of reactively co-sputtered titanium chromium nitride nanopyramids towards flexible supercapacitor with Li-ion storage

The present study reports a flexible symmetric supercapacitor (FSSC) device composed of titanium chromium nitride (Ti-Cr-N) nanocomposite possessing uniform distributed nanopyramids deposited directly over flexible stainless-steel mesh (SSM) via reactive magnetron co-sputtering. The development of Ti-Cr-N/SSM thin film electrodes (TFEs) is optimized by varying the titanium (Ti) target's sputtering power. Increasing the titanium concentration in the Ti-Cr-N thin films enhances the electrochemical performance of Li-ion storage, potentially due to the enhanced synergism resulting in improved electrical conductivity, higher ionic conductivity, and increased surface area. The best-performing Ti-Cr-N/SSM TFE with similar to 11.41% Ti-concentration delivers an excellent specific capacitance of 263.75 F/g (or 40.3 mF/cm(2)) at an applied current density of 0.32 A/g in 1 M Li2SO4. Insights into the charge-storage mechanisms reveal the dominating existence of surface-limited capacitive and pseudocapacitive processes with only minor involvement of diffusion-controlled faradaic processes. Furthermore, the assembled Ti-Cr-N/SSM parallel to Ti-Cr-N/SSM FSSC device manifests a maximum energy density of 9.27 Wh/kg along with the highest power density of 13.71 kW/kg while preserving similar to 82.32% electrochemical stability during 4500 continuous charge-discharge cycling. Moreover, a remarkable mechanical stability of similar to 90% at a 90 degrees bending angle for the FSSC over 600 GCD cycles demonstrates the Ti-Cr-N nanopyramid's superior resilient structural strength. Therefore, the current Ti-Cr-N nanopyramids-based FSSC offers considerable potential application as an alternative energy storage system in next-generation flexible electronics.