*3.1.1 Polymer/CNT nanocomposites*

The nanoscale CNTs amalgamation into a polymer system highly modifies the properties of composites even at a particularly low content of filler. As explained earlier, CNTs are the strongest and hardest fibers ever known. The excellent mechanical and other physical properties of CNTs demonstrate huge potential applications of Polymer/CNT nanocomposites which are one of the most studied systems. Polymer matrix can be easily fabricated without disturbing CNTs by conventional manufacturing techniques resulting in cost reduction for mass production of nanocomposites

#### *Improved Nanocomposite Materials and Their Applications DOI: http://dx.doi.org/10.5772/intechopen.102538*

in the future [35]. Paul et al. [36] synthesized polypyrrole (PPy) and MWCNTs nanocomposites with different compositions by chemical oxidative polymerization method. Polypyrrole (PPy)/MWCNT have been effectively used as supercapacitor devices. Béguin and his research group studied conducting polymer and CNTs based nano-electrodes with improved mechanical, thermal, and electrical properties [37]. PANI/ MWCNT nanocomposite with a specific capacity of 440 Fg−1 at 5 mVs−1 and capacitance retention of 93% after 1000 cycles was reported [38]. Lezak et al. [39] prepared polyaniline (PANI) as an intrinsically conducting polymer and poly (vinylidene fluoride) (PVDF) and MWCNTs.

#### *3.1.2 Activated carbon/CNT nanocomposites*

Activated carbon, also known as activated charcoal, is a carbon type that is treated with tiny volume holes to improve the surface area. One gram of activated carbon, due to its increased microporosity, has a surface area of more than 3000m<sup>2</sup> /g calculated by gas adsorption [40]. Activated carbon (AC)/CNTs nanocomposites are superior materials having AC as matrix material and CNTs as fillers. Numerous researchers have used activated carbon for production of CNT nanocomposites. Huq et al. [41] studied the preparation of AC and CNTs based supercapacitors by a superficial electrophoretic deposition (EPD) method. In this study, the as-prepared AC/CNT electrode had capacitance maintenance of 85% after 11,000 cycles. In EDLC electrode, activated carbon has been used for an extensive period due to its high capacitance, low cost, and long cycle life [42]. Qiu et al. [43] prepared activated carbon fibers (ACHFs) combined with carbon nanotubes and nickel nanoparticles (CNTs-Ni-ACHFs) by thermal reduction and chemical vapor deposition method. Usually activated carbon, due to its very high surface area, is used as an absorbent [44].
