Chapter two - Fundamental electrochemical energy storage systems

Abstract

To power our communities’ portable electronics and to electrify the transport sector, electric energy storage (ESE), which takes the form of batteries and electrochemical condensers, is commonly used. Another EES application combining this technology and renewable power sources such as solar and wind to power the electricity grid was introduced by the evolving requirement to overhaul the energy grid in many developed countries together with the projected growth of worldwide energy consumption in the coming decades. A major need for energy storage is generated by the fluctuation in demand for electricity and unreliable energy supply from renewable sources, such as the solar sector and the wind. Current storage techniques like batteries or supercapacitors are either short in terms of electricity production or of their energy storage capacity. The pseudocapacitors incorporate all features to allow the power supply to be balanced. The load and discharge rates are high and can store far more power than a supercapacitor. Electrochemical energy storage is based on systems that can be used to view high energy density (batteries) or power density (electrochemical condensers). Current and near-future applications are increasingly required in which high energy and high power densities are required in the same material. Pseudocapacity, a faradaic system of redox reactions to the ground or close to the surface, provides a way to achieve high energy density at high load discharge rates. When markets for digital consumer products and electrical transport grow and energy storage technology for renewable energy sources begins to emerge, EES will continue to be relevant. There is a need for vast amounts of power to be instant, within seconds or minutes, in particular for transport and storage applications for the grid. Although the required power density is possible with carbon-based electrochemical capacitors, their relatively small energy density limits their usefulness. This chapter discusses for the first time fundamental electrochemical theories and the basic measurement methods used to describe capacitive characteristics. This chapter may give descriptions of how pseudocapacitive materials can be used, based on these basic characteristics.