Keywords: carbon nanotubes, Boron nitride nanotubes, high temperature, energy storage, aerospace and radiation protection applications
Summary:During the last two decades, applications of carbon nanotubes (CNTs) have been on the increase as structural elements in mechanical, thermal and electrical systems mostly because of enhanced properties resulting better flexibility, improved conduction and reduced weight. The remarkable large surface area and porosity of CNTs are being used for additional applications such as energy storage in batteries and supercapacitors; energy production in solar cells, fuel cells and thermoelectric generators and energy transmission in conducting wires and coatings. It is noted that the CNTs are easily oxidized at temperatures beyond 800K and therefore limits their high temperature applications for propulsion and thermal protection under atmospheric reentry conditions. The discovery of Boron Nitride Nano Tubes (BNNTs) and recent advances in large scale synthesis will provide alternatives to CNTs. This paper will highlight the recent advances in the synthesis, processing and applications of this new nanomaterial that may surpass carbon nanotubes (CNTs). Nanomaterials (NMs) such as CNTs, BNNTs and metal oxides have been in use for the development of cleaner and higher performance next generation energy devices with enhanced energy efficiencies. Innovative methods of using these nanomaterials will be a key to sustainability of global resources. In addition to mechanical improvements of maintaining strength at reduced weight, some of these NMs provide enhanced electrical, magnetic and thermal properties to replace conventional materials. In this review, different methods of synthesis of BNNTs including laser, CVD and RF discharge will be compared. Current and future applications in mechanical structures, radiation shields, piezoelectric actuators, medical devices and thermal management systems are presented.