Interdigitated flexible supercapacitor using activated carbon synthesized from biomass for wearable energy storage

TL;DR

This paper presents a flexible, biomass-derived activated carbon supercapacitor with high energy density, mechanical durability, and suitability for wearable electronics, fabricated via low-cost screen printing techniques.

Contribution

It introduces a novel, low-cost fabrication method for flexible supercapacitors using biomass-derived activated carbon and screen printing, suitable for wearable devices.

Findings

High capacitance of 33.18 mF/cm2 at 1mV/s

Energy density of 5.87 micro Wh/cm2

Retains 90% capacity after 5000 bending cycles

Abstract

We have developed a flexible, interdigitated supercapacitor with high energy storing capacity for wearable, flexible electronic application. Locally obtained low cost biomass (banana peel) was impregnated with KOH under high temperature under an inert atmosphere to synthesize activated carbon with significant Brunauer Emmett Teller surface area of 62.03m2/g. The supercapacitor was fabricated by screen printing interdigitated current collector of conducting silver ink on a thin flexible PET substrate and subsequent deposition of activated carbon and drop casting of gel electrolyte. Fabricated supercapacitor exhibits high capacitance of 33.18 mF/cm2 at 1mV/s scan rate and 20.12 mF/cm2 at a discharge current of 1mA and high energy density of 5.87 micro Wh/cm2. The developed flexible supercapacitor retains its energy storing capacity (90%) over several cycles of mechanical bending and repetitive electronic cycling tests (5000 cycles). Locally available biomass based activated carbon and low cost screen printing technique can be used for large scale fabrication of supercapacitor. The flexible supercapacitor demonstrates high energy storing capacity and mechanical durability through multiple bending and charging and discharging through LED. Therefore, it can be used for further developing integrated wearable and printed electronic devices.