Carbon nanotubes (CNT) represent one of the most unique materials in the field of nanotechnology. CNT are the allotrope of carbon having sp2 hybridization. CNT are considered to be rolled-up graphene with a nanostructure that can have a length to diameter ratio greater than 1,000,000. CNT can be single-, double-, and multi-walled. CNT have unique mechanical, electrical, and optical properties, all of which have been extensively studied. The novel properties of CNT are their light weight, small size with a high aspect ratio, good tensile strength, and good conducting characteristics, which make them useful for various applications. The present review is focused on the structure, properties, toxicity, synthesis methods, growth mechanism and their applications. Techniques that have been developed to synthesize CNT in sizeable quantities, including arc discharge, laser ablation, chemical vapor deposition, etc., have been explained. The toxic effect of CNT is also presented in a summarized form. Recent CNT applications showing a very promising glimpse into the future of CNT in nanotechnology such as optics, electronics, sensing, mechanical, electrical, storage, and other fields of materials science are presented in the review.

The bipolar plate is the most important and most costly component of proton exchange membrane fuel cells. The development of a suitable low density bipolar plate is scientif-cally and technically challenging due to the need to maintain high electrical conductivity and mechanical properties. Here, bipolar plates were developed from different particle sizes of natural and expanded graphite with phenolic resin as a polymeric matrix. It was observed that the particle size of the reinforcement significantlyinfluencesthe mechanical and electri-cal properties of a composite bipolar plate. The composite bipolar plate based on expanded graphite gives the desired mechanical and electrical properties as per the US Department of Energy target, with a bulk density of 1.55 g.cm-3 as compared to that of ~1.87 g.cm-3 for a composite plate based on natural graphite (NG). Although the bulk density of the expanded-graphite-based composite plate is ~20% less than that of the NG-based plate, the I-V perfor-mance of the expanded graphite plate is superior to that of the NG plate as a consequence of the higher conductivity. The expanded graphite plate can thus be used as an electromagnetic interference shielding material.