Page 268 - Polymer-based Nanocomposites for Energy and Environmental Applications

240 Polymer-based Nanocomposites for Energy and Environmental Applications

and conducting materials. These electrode materials are still not the ideal materials.
There are still several challenges that have to be overcome for the more widespread
large-scale commercialization of the ESS. In the last decade, extraordinary new mate-
rials called polymer nanocomposites have been explored as material for the electrodes
and the electrolyte. In this chapter, synthesis, properties, and applications of various
types of polymer nanocomposites for their application as components of electrochem-
ical energy storage materials are briefly presented. An up-to-date account of latest
advancements in the development of polymer nanocomposite materials for their appli-
cation as electrode and electrolyte material for supercapacitor, secondary recharge-
able batteries, and polymer electrolyte membrane fuel cells (PEMFCs).

9.2 Polymer nanocomposites

Nanocomposite materials are hybrid materials of two or more materials with very dis-
similar physical and chemical properties that remain separate and distinct on a mac-
roscopic level and with one of the constituents having at least one dimension in
between 1 and 100 nm size range [13,14]. There are two components of a
nanocomposite material. One is the matrix or the bulk material and other one is the
inorganic nanofiller. If a polymer serves as the matrix whereas the inorganic nano-
material acts as nanofiller, then the material is called the polymer nanocomposite
[15,16]. The polymer nanocomposite materials display extraordinary properties com-
pared with the polymer composite with micron-size fillers due to the synergic inter-
action between the polymer and the nanomaterial filler owing to their “nanoeffect”
[17]. Only small amount of nanomaterial as filler can give rise to great property
enhancement of the polymeric materials. The nature and properties of the polymer
used as matrix for polymeric nanocomposites (PNCs) along with the nanofiller have
great effect on the electric conductivity, ease of processing, ionic conductivity, tensile
strength, and chemical, thermal, and mechanical stability. Polymers can be classified
in terms of their polymerization mechanism, as addition polymers or condensation
polymer, or by their thermal processing as thermosetting or thermoplastic polymers
[18,19]. However, for the applications in electrochemical systems, two types of poly-
mers are of considerable interest: (a) electric conducting polymers and (b) ion con-
ducting polymers. Conducting polymers are the class of polymers that unlike the
conventional polymers show significantly electric conductivity. These are mainly
composed of organic monomers with conjugating double bonds [20,21]. Polyaniline
(PANI), polypyrrole (PPy), polythiophene (PTh) are some of the most intensely
explored conducting polymers for various practical applications, including for energy
storage [15,21–26]. These materials, in fact, combine the good electric properties with
the properties of conventional polymers such as low cost, light weight, good process-
ibility, mechanical flexibility, and thermal stability [27]. Nanofillers are used to
improve the properties of the polymeric materials for their potential application as
material for energy storage devices. So far in the literature metals, metal oxides,
ferromagnetic materials, carbon, carbon nanotubes (CNTs), graphene, layered sili-
cates, dendrimers, and titanium nanotubes have been used as filler materials