Doped Carbon Nanotubes for Energy Storage

Doped carbon nanotubes (CNTs) exhibit special and enhanced properties that are desirable in many applications. But to have a proper grasp of how they perform, to ensure that they're performing to the specification, they must be characterized with care. Here are some of the most important methods for characterising doped carbon nanotubes:

Transmission Electron Microscopy (TEM) and High-Resolution Transmission Electron Microscopy (HRTEM): Used to detect the structure and shape of carbon nanotubes. For instance, TEM and HRTEM can detect the dimension, dispersion and lattice fringe of doped carbon nanotubes.

Atomic Force Microscopy (AFM): AFM measures height and roughness of carbon nanotubes for understanding their structure and distribution. AFM can, for instance, prove the height and spread of doped carbon nanotubes.

Raman Spectroscopy: Raman spectroscopy can be a very useful technique for characterizing the carbon nanotubes to look for defects, lattice vibration modes, etc. Changes in the G-band and D-band can be used, for instance, to identify the doping effect of carbon nanotubes from Raman spectroscopy.

X-ray Diffraction (XRD): The crystal structure and lattice properties of carbon nanotubes are determined by XRD. So, for instance, the crystal plane diffraction peaks of doped carbon nanotubes can be determined using XRD, which also tells us about the crystal structure.

Fourier Transform Infrared Spectroscopy (FTIR): FTIR analysis of chemical functional groups in the carbon nanotube surface. For instance, FTIR could register and alter oxygen-groups in doped carbon nanotubes.

X-ray Photoelectron Spectroscopy (XPS): XPS studies the chemical composition and elemental makeup of the surface of doped carbon nanotubes. For instance, XPS can determine what chemical bonds the dopant elements share.

Scanning Electron Microscopy (SEM): The macroscopic morphology and surface properties of carbon nanotubes are measured using SEM. SEM can show, for instance, the diameter, length and surface shape of doped carbon nanotubes.

Electron Energy Loss Spectroscopy (EELS): EELS is used to study the electronic composition and defect states of carbon nanotubes. EELS can observe electron transfer and defect formation, for instance, in doped carbon nanotubes.

It is critical to define doped carbon nanotubes in order to understand their special properties and prepare them for future application. SEM, TEM, Raman spectroscopy, XPS and others combine to give us the complete picture of the structural, chemical and electrical structure of doped CNTs. With these characterization techniques, suppliers and scientists can take advantage of the potential of doped CNTs in electronics, energy storage, composites and beyond.

Applications of Doped Carbon Nanotubes
The applications for doped carbon nanotubes (CNTs) are many, in part because doping techniques can significantly alter the electronic composition and behavior of carbon nanotubes. Doping is normally achieved by adding nanoparticles of heteroatoms (boron, nitrogen, sulphur, phosphorus etc.) In the carbon nanotubes which brings new features and properties.

Electrochemical Performance: Doped carbon nanotubes perform very well in the electrochemical sphere. N-doped carbon nanotubes, for example, are very electrocatalytic in ORR, and thus a candidate for fuel cells and metal-air batteries. Moreover, nitrogen/sulfur co-doped carbon nanotubes are also extremely electrochemically strong, which can be applied to supercapacitors.

Energy Storage: Carbon nanotubes dotted with an anti-microbial layer work brilliantly in lithium-ion batteries and supercapacitors. Nitrogen-doped carbon nanotubes, for instance, can boost the storage capacity of lithium-ion batteries; boron-doped carbon nanotubes improve the field emission of multi-walled carbon nanotubes, important for high power density electronics.

Catalytic Performance: Doped carbon nanotubes act as catalyst carriers and are good at all the catalytic reactions. Nitrogen-doped carbon nanotubes, for example, are very active in electrocatalytic oxygen reduction reactions with enormous potential to be used in environmental and energy-conversion technologies. Boron-doped carbon nanotubes also effectively adsorb gases such as formaldehyde, and have a high catalytic activity.

Composites: Carbon nanotubes are common in composites. Boron-doped carbon nanotubes, for instance, can be used to create high-performance composites like boron-doped carbon nanotube/cement composites and boron-doped carbon nanotube/magnesium composites. Such composites have high potential applications in building, aircraft, etc.

Sensors: The application of enriched carbon nanotubes extends into the area of sensors too. Boron-doped carbon nanotubes, for example, could be used to develop electrochemical biosensors that are sensitive and reproducible, which can be used for drug discovery and early disease detection.

Environmental Protection: Doped carbon nanotubes can also be useful in conservation. For instance, tin-doped carbon nanotubes (due to their chemical and catalytic properties) are particularly promising for environmental remediation.

Doped carbon nanotubes are very promising across multiple fields but they also still need to deal with the issue of dopant implantation, doping depth and doping concentration. Next generation studies will have to further hone doping approaches to achieve better-performing doped carbon nanotubes and make them available in more applications.