Supercapacitor vs Battery & Capacitor

In this era of climate change, there is a need to switch from fossil fuels to electric power. Electricity is a versatile form of electricity but it has one problem associated with it. As I had raised same concern in my last post that there is a problem to store electricity for a long time (https://imbibephysics5794.blogspot.com/2020/08/decarbonisation-and-storing-thermal.html). For capacitors and batteries we need to look for two different things, one is amount of charge stored and other is how quickly the energy is delivered. Capacitors deliver energy instantaneously but cannot able to store large amount of charge. Batteries have an ability to store large charge and cannot give energy quickly. So in order to overcome these drawbacks, we need to look for other alternatives. This problem can now be solved by supercapacitors.

SUPERCAPACITORS

Supercapacitor also known as ultracapacitor is an electronic device which is used to store large amount of electric charge. According to following formula, it is cleared that capacitance is directly proportional to surface area and is inversely proportional to distance between the plates.

C = Ɛ_oA/d

How supercapacitors are different from conventional capacitors and batteries?

    Supercapacitors consist of electrodes of large surface area and a thin dielectric plate between electrodes so to have large capacitance. Supercapacitors can store 100 times more charge than a conventional capacitors. Here, electrodes are made up of some porous substance which provides more surface area for storage of charge. In supercapacitors there is no dielectric material between the plates. Both electrodes are soaked in specific electrolyte and are separated by very thin layer of insulator. Plastic, paper or carbon can be used as insulator. That’s why supercapacitors could able to store larger charge because of large surface area of electrodes and lesser distance between them.

    Supercapacitors rely on static charges resting on solid electrodes while batteries rely on the charges which produced through chemical reactions of liquids present in batteries. Batteries have higher energy density while supercapacitors have higher power density. All these factors gave us conclusion that supercapacitors releases energy very quickly as compare to batteries.

Future of supercapacitors

Scientists believe that supercapacitors may replace lithium ion cells as it charges more quickly and can recharge multiple numbers of times.

Scientists are exploring the concept of designing lightweight supercapacitors by designing ECs with graphene which will have high storage capabilities.

Supercapacitors can widely be used in automobiles where regenerative braking is used, in wind turbines, motors and also it been employed in hybrid buses.

By looking its applications it seems that supercapacitors or ultracapacitors are a most promising energy storage device.