Development of highly efficient supercapacitor based on a ternary (Sr(OH)2/CoO(OH)/Mn(O)2) composite: With tuberose mesoporous nanospheres structure

Abstract

In recent years, metal oxides/hydroxides have surfaced as an encouraging category of materials in pursuit of finding efficient and sustainable solutions for energy conversion/storage. This report highlights the binder-free synthesis of a ternary composite electrode based on Sr(OH)2/CoO(OH)/MnO2 material using a chemical LBL approach. The XRD analysis revealed that the sample had an amorphous nature, while FTIR disclosed the different functional group present in the sample. Surface architecture and insight view were analyses using high-resolution SEM, FESEM, and TEM. The composite formation was confirmed via EDX, mapping, and XPS analysis, while the specific surface area was estimated using BET characterization. The prepared ternary electrode delivers the highest value of specific capacitance of 1206 F g−1 @ 5 mV/ s sweep rate within a potential window of 0.5 V (−0.1 to 0.4 V) in a 6 M KOH electrolyte. It shows 94 % capacitance retention after 10,000 continuous iteration of GCD cycles. A symmetric solid-state prototype device with 6 M KOH/PVA gel electrolyte was designed for real time practical application. The obtained electrochemical response gives the outstanding value of specific capacitance of 301.2 F g−1 @ 5 mVs−1 and cycle stability of 83 % up to 10,000 GCD cycles. The device attained energy and power densities of 51.1 W h Kg−1 and 4959.6 W Kg−1 respectively. The fabricated prototype device was proficient in glowing red, blue, green, white, and a panel of 56 red LEDs. Additionally, the aging impact and flexibility test have also been carried out. The device withstood a 180° bend and showed no change in electrochemical performance even after 2 months from its fabrication. A self-proposed charge storage mechanism has also been presented for better understanding to the readers. Hence, the results obtained from both the composite electrode and the device are highly encouraging and fruitful for the next generation energy technology.