ACTIVATED CARBON FROM PLANT-BIOMASS WASTE MATERIALS AS PROMISING ELECTRODES FOR SUPERCAPACITOR APPLICATIONS

ABSTRACT

This work is aimed at studying activated carbons as supercapacitor electrode materials derived from plant biomass waste materials. The activated carbon raw materials are sourced from coconut shell, pine cone and rice husk plant biomass. The chemical activation route is

employed with KOH as an activating agent. The carbonization temperature used is 800 oC and the carbonization time is varied from 1 h to 5 h. Activated carbon of high surface area and porosity are achieved and their electrodes show a good electrochemical performance presenting them as applicable for supercapacitor electrode materials.

CHAPTER ONE

INTRODUCTION

1.1 BACKGROUND

As the global economy constantly continues to rise, the global demand for power and energy sources are synonymously increasing. This raises the consumption of fossil fuels which produces two major related issues; depletion of fossil fuel reserves and environmental greenhouse emission problems which not only pose pollution problems but also climate change issues. These issues have been projected as one of the global urgent and important challenges to be tackled. There is, therefore, a need to develop alternative energy sources that are clean, sustainable, and meet up with the rising global demand. In view of this, a lot of renewable energy sources have been explored but they generally have a commonly associated issue; they are seasonal. Most renewable clean energy sources are highly dependent on the time of day and regional weather conditions. The need for the development of related energy conversion and energy storage devices, therefore, arises in order to take the harnessing of these renewable clean energy sources to their best efficiency. Energy conversion and storage devices showing the greatest potentials currently include; batteries, supercapacitors and fuel cells [1].

1.2 MOTIVATION AND PROBLEM STATEMENT

Supercapacitors are yet to reach their full potential even as energy storage problems persist. Supercapacitors are governed by the same fundamental equations as conventional capacitors, but utilizing higher surface area electrodes and thinner dielectrics to achieve greater capacitances seem to possess the quality for future energy solutions. Fossil-based carbon sources for application as activated carbon materials are limited and non- renewable; biomass-based sources are low-cost high-performance candidates.

1.3 SCOPE AND OBJECTIVE

This work is aimed at studying activated carbon which can serve as the negative electrode material of asymmetric supercapacitors. The activated carbon is sourced from biomass materials of pine cones, rice husks, and coconut shells. The electrochemical and surface area parameters of activated carbon are studied and a comparative study of the different materials is presented with suggested optimization techniques.