A group of researchers from India and South Korea have developed a portable supercapacitor that can be charged using light.
Supercapacitor
- Supercapacitors are a type of an electrochemical energy storage systems which have great power density and specific capacitance.
- Supercapacitor differs from ultracapacitor as they are built from different materials and structured in slightly different ways, so they store different amounts of energy.
- A supercapacitor device consists of an electrode, electrolyte and a current collector.
- A capacitor stores energy by means of a static charge as opposed to an electrochemical reaction.
- Applying a voltage differential on the positive and negative plates charges the capacitor.
- They present lower energy densities (they store less energy per unit mass) than batteries.
- Applications – Portable and wearable devices such as smartphones, tablets, laptops and smartwatches.
Advantages of Supercapacitors
- Quick charging and discharging
- Exhibit long life since they are not subject to chemical degradation as in conventional batteries
- Greater power density (can release energy more quickly)
- Smaller in size
- Provides back-up power during power outages in space applications
- Have little or no internal resistance (they store and release energy without using much energy)
- Work at very close to 100% efficiency (97–98% is typical)
Light-powered Supercapacitors
- The researchers developed a design involving a stainless steel electrode with a quartz transparent window in order to harvest visible light.
- A specially prepared ‘down-conversion’ phosphor is introduced before the quartz window to facilitate light-induced charging.
- Devices that are powered by such supercapacitors can be charged by simply keeping them under light.