Bangalore: Researchers from IIScinstrumentation department applied Physic (IAP) have designed a novel ultra-micro supercapacitora tiny device capable of storing an enormous amount of electrical charge.
According to the institute, the new device is much smaller and more compact than existing supercapacitors and can potentially be used in many devices ranging from street lights to consumer electronics, electric cars and medical devices.
“Most of these devices currently run on batteries. However, over time, these batteries lose their ability to store charge and therefore have a limited lifespan. Capacitors, on the other hand, can store electrical charge for much longer, by virtue of their design,” IISc said in a statement.
For example, a capacitor running at 5 volts will still run at the same voltage even after a decade. But unlike batteries, they cannot be discharged. energy constantly, to power a mobile phone, for example.
“Supercapacitors, on the other hand, combine the best of batteries and capacitors: they can store and release vast amounts of energy and are therefore highly sought after for next-generation electronic devices,” IISc said.
In the current study, published in ACS energy chartsThe researchers made their supercapacitor using field-effect transistors, or FETs, as charge collectors, instead of the metal electrodes used in existing capacitors.
“Using FETs as an electrode for supercapacitors is something new for adjusting the charge on a capacitor,” said Abha Misra, a professor at IAP and corresponding author of the study.
Current capacitors typically use metal oxide-based electrodes, but are limited by poor electron mobility, IISc said, adding that Misra and his team therefore built hybrid FETs consisting of alternating disulfide layers. molybdenum (MoS2) a few atoms thick and graphene, to increase the mobility of electrons, which are then connected to gold contacts.
A solid gel electrolyte is used between the two FET electrodes to build a solid state supercapacitor. The entire structure is built on a silicon/silicon dioxide base.
“The design is the critical part, because you are integrating two systems,” Misra said, adding that the two systems are the two FET electrodes and the gel electrolyte, an ionic medium, which have different charge capacities.
Once the supercapacitor was made, the researchers measured the device’s electrochemical capacitance, or charge-holding capacity, by applying various voltages.
“They discovered that, under certain conditions, the capacitance increased by 3000%. By contrast, a capacitor containing only MoS2 with no graphene showed only an 18% improvement in capacitance under the same conditions,” added IISc.
Vinod Panwar, a PhD student at IAP and one of the lead authors, adds that it was a challenge to fabricate the device to get all the ideal characteristics of the transistor. “Since these supercapacitors are very small, they cannot be seen without a microscope, and the manufacturing process requires high precision and hand-eye coordination,” Pawar said.
In the future, the researchers plan to explore whether replacing MoS2 with other materials can further increase the capacitance of their supercapacitor. They add that their supercapacitor is fully functional and can be implemented in energy storage devices such as electric car batteries or any miniaturized system via on-chip integration. They also plan to apply for a patent on the supercapacitor.
