Guwahati, May 10: Researchers from Indian Institute of Technology-Guwahati (IIT-G) have developed novel materials and methodology that significantly enhances the performance metrics of supercapacitors.
Led by Uday Narayan Maiti from the department of physics, IIT-G, the findings of the research have been published in the prestigious journal, Small, published by Wiley-VCH.
Supercapacitors, akin to batteries, serve as energy storage devices. However, unlike batteries that rely on chemical reactions, supercapacitors store energy through the electrostatic field – the separation of charges.
“Renowned for their remarkable efficiency, supercapacitors can complete rapid charging and discharging cycles in mere seconds. Powering quick-charging devices such as digital cameras and LED flashlights, supercapacitors boast charging times as short as 90 seconds,” a statement issued by IIT-G on Friday said.
“Supercapacitors prove indispensable in applications requiring bursts of power over short periods, such as defibrillators used for heart stabilisation and power stabilisation in devices like laptops,” it said.
However, despite their exceptional energy storage properties, supercapacitors face challenges in widespread commercialisation. For any supercapacitor technology to achieve commercial success, it must simultaneously meet three critical performance metrics – gravimetric capacitance, volumetric capacitance and areal capacitance.
Areal capacitance is crucial for designing compact and lightweight energy storage solutions. However, achieving high areal capacitance necessitates large amounts of energy-storing active materials for the electrodes, resulting in a trade-off with volumetric and gravimetric capacitances.
To tackle this challenge, Maiti’s team introduced a composite electrode comprising MXene and bio-waste-derived cellulose nanofibers (CNF). MXenes represent two-dimensional inorganic materials comprising extremely thin layers of transition metal carbides, nitrides or carbonitrides.
In this study, the team used a novel electric-field guided method to assemble these extremely thin and small nanomaterials to form the electrodes.
“The MXene-CNF-hydrogel-derived electrodes exhibit impressively high areal and volumetric capacitance with very high areal mass loading more than 70 mg/cm2. They maintain 96 percent of their capacitance after 20,000 charge-discharge cycles, showcasing robust long-term operational stability,” Maiti said.
The researchers assembled MXene sheets into porous hydrogel structures – gels that retain a significant amount of water. They found that dehydration of these hydrogels resulted in the creation of blocked localised pores. The introduction of CNFs derived from garlic husk interconnected the pores and facilitated ion transport.