Carbon Nanotube Films for Energy Applications

Carbon Nanotube Films for Energy Applications


This perspective article describes the application opportunities of carbon nanotube (CNT) films for the energy sector. Up to date progress in this regard is illustrated with representative examples of a wide range of energy management and transformation studies employing CNT ensembles. Firstly, this paper features an overview of how such macroscopic networks from nanocarbon can be produced. Then, the capabilities for their application in specific energy-related scenarios are described. Among the highlighted cases are conductive coatings, charge storage devices, thermal interface materials, and actuators. The selected examples demonstrate how electrical, thermal, radiant, and mechanical energy can be converted from one form to another using such formulations based on CNTs. The article is concluded with a future outlook, which anticipates the next steps which the research community will take to bring these concepts closer to implementation.Get more news about carbon nanotube film seller,you can vist our website!

The global energy demand continues to rise at a staggering rate. Ritchie and Roser showed that in the last 100 years, world energy consumption increased from ca. 18,000 TWh in the 1920s to ca. 160,000 TWh in 2018 [1]. Change by orders of magnitude was deemed necessary to support the development of civilization, in which energy is now utilized in many ways. It is evident that the times when energy was mainly used only for heating, cooking, or simple processing are long gone. At present, much more advanced applications are the reality. We manage various forms of energy in our daily life without even noticing. A simple smartphone or computer, on which you are reading this paper, is a multifunctional tool that transforms various forms of energy in the background to enable the device to serve its purpose.
Various materials can be used to mediate the conversion of one form of energy into the other. The discovery of nanomaterials revealed that they can be handy for this purpose due to their unique properties as they are constrained to 0D, 1D, or 2D architectures [2,3,4,5]. Specifically, carbon nanomaterials, such as carbon nanotubes (CNTs) or graphene, have shown a remarkable performance on this front ever since these materials were made famous at the turn of the XX and XXI century [6,7]. Properties such as ballistic conduction [8], remarkable thermal conductivity [9], or unparalleled strength [10] have attracted a significant share of the scientific community, which in turn has laid the foundation for the development of a wide range of applications. Most of the applications relevant to these properties require the material to take the form of macroscopic networks, such as films [11] or fibers [12], to exploit the merits of the material on a real-life scale. Over the years, many techniques have been devised for how such networks can be manufactured. These ensembles are lightweight [13,14], flexible [15], resistant to extreme operational conditions [16,17], and can be produced from sustainable sources [18], which is essential from the environmental point of view. Interestingly, the characterization of carbon nanomaterials has demonstrated that they have enormous utility potential in energy conversion and storage [19,20,21] applications, especially when used in the form of the aforementioned networks.
In this perspective article, the most promising exploitation areas for macroscopic CNT films for energy management are showcased. The report begins with a description of the mainstream methods used to produce such macrostructures. A range of applications concerning electrical, thermal, radiant, and mechanical energy are presented. The contribution is concluded with a summary of the main findings enclosed herein. Finally, future perspectives for the utilization of CNTs in these scenarios are also provided to indicate gaps in knowledge which should be solved. Exploring these new research directions should provide a more thorough understanding of the nature of nanocarbon, which eventually should bring it closer to the appropriate technology readiness level necessary for implementation. Transparent coatings are not considered extensively in this article, so readers are advised to seek information regarding this topic in other dedicated reviews [22,23].
2. Synthesis of CNT Films
There is an assortment of techniques for how one can obtain CNT films (Figure 1). These can be divided into liquid- and solid-based methods. In the first category, a liquid medium is required wherein CNTs are dispersed. Van der Waals forces between them are collectively strong, so some sort of agitation must be applied to overcome these interactions and cause individualization. Standard techniques to accomplish this goal involve either sonication [24] or shear mixing [25], which deliver sound and mechanical energy, respectively. Simultaneously, to improve the compatibility of CNTs with the solvent (particularly with water), oxidation of the material is conducted before the dispersion step [26,27]. This introduces appropriate functional groups, which increase the affinity of CNTs to the liquid medium. Since oxidation is most commonly disruptive in nature and deteriorates the properties of the material, another popular route is to focus on physical interactions. In such a case, surfactants are used to make CNTs compatible. Amphiphilic chemical compounds, such as sodium dodecyl sulfate [28], sodium dodecylbenzene sulfonate [29], cetyltrimethylammonium bromide [30], or Pluronic [31], can all be engaged for this purpose. Regardless of the surfactant type (anionic/cationic/non-ionic/amphoteric), these species improve the dispersibility of CNTs in liquid medium by mediating the interaction between the medium and the CNTs.