SUPERCAPACITOR PERFORMANCE OF OPEN FRAMEWORK-DERIVED NICKEL PHOSPHATE AND NICKEL-COBALT PHOSPHATE

• Main Author: Raissa
• Format: Dissertations
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/81014
• Institution: Institut Teknologi Bandung

Supercapacitors possess exceptional characteristic that make them highly promising for energy storage applications. These include their impressive power density, rapid charge-discharge kinetics, and long lifespan. However, the energy density of supercapacitors needs to be enhanced as it currently falls behind that of batteries. Using battery-type electrodes in supercapacitors allows for increased energy density due to their reversible redox reactions. Open-framework materials like Versailles Santa Barbara – 5 (VSB-5) and Metal Organic Framework (MOF) show great potential as electrode candidates because of their high surface area and porosity. Nevertheless, the low conductivity of these materials hinders their practical implementation in supercapacitors. To tackle this challenge, a new method can be employed: transforming these open-framework materials into phosphates. This dissertation delves into a comprehensive examination of the conversion process. Firstly, VSB-5 is converted through calcination at temperatures ranging from 300 to 800°C. The results indicate that the sample heated at 600°C exhibits the highest specific capacity of 516 C g?¹ at 0,62 A g?¹. An energy density of 52 Wh kg?¹ at 434 W kg?¹ was observed in the formation of an asymmetric supercapacitor utilizing phosphate and activated carbon. Secondly, the conversion of MOF into phosphate involves the variation of the Ni/Co mol ratio (10:1, 1:1, 1:10). The findings reveal that the phosphate sample with a Ni/Co ratio of 10:1 exhibits a capacity of 522 C g?¹ at 0,5 A g?¹, surpassing its precursor MOF (437 C g?¹ at 0.5 A g?¹). Moreover, assembling an asymmetric supercapacitor with this phosphate and activated carbon achieves an energy density of 22 Wh kg?¹ at 363 W kg?¹. Finally, the third study delves into the conversion of NiCo-MOF into phosphate. However, in this instance, the MOF synthesis includes PVP as a stabilizer, with variations in cobalt content at 10%, 20%, and 30% mol. The results demonstrate that the phosphate derived from NiCo-MOF with 30% cobalt content exhibits a capacity of 857 C g?¹ at 0,5 A g?¹, surpassing its MOF precursor (393 C g?¹). Furthermore, the asymmetric supercapacitor assembled with this phosphate achieves a maximum energy density of 14 Wh kg?¹ at a power density of 363 W kg?¹. The study highlights the significant improvement in electrochemical performance of these materials when converted to phosphates. This development holds great potential for advancing supercapacitor technology and addressing the challenges in energy storage systems.