Unlike batteries, which generate electricity through electrochemical reactions only, microsupercapacitor (MSC) stores energy efficiently via both electrochemical reaction as well as using electric double charge layer phenomena to provide much higher power density. So far, the developed MSCs are bulky in nature and can only store limited amount of energy due to the availability of limited space and also involves the complicated fabrication processes. Modern electronic devices that are compact and lightweight require an alternate energy storage system compatible with these devices. Reducing MSC size effectively without losing efficiency is a major challenge. The simple spray deposition technique is developed to overcome these issues. Spray deposition employs ink of electroactive materials, e.g., carbon nanotubes, reduced graphene oxide and manganese dioxide, etc that is spray deposited on any substrate including metals and polymers. The layer-by-layer patterning of hybrid nanomaterials ink increases the overall electrochemically active surface area by offering large surface-to-volume ratio and boosts the movement of charges, making the overall energy storage capacity efficiently than existing supercapacitors. Lightweight and efficient, materials such as carbon nanotubes or reduced graphene oxide are used to prepare the electrodes.
MSCs can actually be printed anywhere, on any substrate; thus, they can easily be mounted on any surface just like a simple spray on the walls or any rough surface etc. with the power density of up to 100 µW/cm2 (~ 43.5 W/cm3). Moreover, the new MSCs can also be recharged with much higher frequency than the usual batteries and thus have longer life. The MSC can be charged and discharged more frequently as compared to battery up to 10,000 cycles that can certainly be extended further based on the requirement. On flexible substrate like polymer sheet that is bendable, the MSCs performance is tested for many bent angles. The response demonstrated a stable energy storage capacity to retain the power in spite of bent structure. The immediate application of this foldable MSC is in flexible electronic displays. Definitely, this type of in-plane MSC can be used in green vehicles by integrating them in series and parallel connections.
Website URL: http://iap.iisc.ac.in/~abha/