Polymer Functionalized Graphene in Energy Storage Devices

Abstract

In this chapter the applications of polymer functionalized graphene (PFG) in a solid state battery and supercapacitors are discussed. In a solid state battery the use of PFG as anode, cathode and electrolyte are discussed with some examples. Electrode materials with rapid charge and discharge rates in lithium ion batteries (LIBs) using PFG are noted. They also exhibit long cycle life, high energy density and excellent rate capability, with high reversible Li+ storage capacity and rapid Li+ transport. Solid polymer electrolyte (SPE) materials with reduced crystallinity and higher ionic conductivity is very much necessary and here their development is discussed using PFG. PFG is highly used in flexible supercapacitors because of the large specific surface area, high mechanical stability and good conducting properties of graphene or reduced graphene oxide (RGO). Controlled reduction of GO is found to behave as a good supercapacitor and hence functionalization of GO/RGO with conducting polymers are found to be very useful as electrode material for increasing the specific capacitance of the supercapacitor devices. Here polymer functionalization of GO both by covalent and noncovalent ways are discussed for their use as electrode materials of supercapacitors. The specific capacitance, power density, energy density, cyclic stability, including Ragone plot, etc., for all the systems are discussed making the use of three electrode and two electrode systems during the use of cyclic voltammetry (CV) technique in the presence of an electrolyte which is mostly acids or ionic liquids. Variation of specific capacitance with different current densities are discussed for their utility in practical application. Both symmetric and asymmetric super capacitor devices fabricated with PFG electrodes are also discussed with an aim to improve the specific capacitance of the device and also for their long term stability.