Graphene-based materials | Graphene is one of the most astonishing discoveries of the twenty-first century, and graphene-based materials are at the forefront of the scientific community’s study. According to the recent research, graphene has long been recognized as the most promising possible candidate for next-generation materials. Graphene has laid the groundwork for a new vista of possibilities for what we can do with materials, and it has completely transformed the way we think about our capabilities as innovators, scientists, and engineers at their absolute limits. Because of its simple, systematic structure, strong, regular, atomic bonding, good heat conductive, and electricity conductive properties, the twenty-first century seems to be the age of graphene. It provided us with the ability to upgrade anything from airplanes to wearable electronics.
What is Graphene-based materials?
Graphene is the rock star in the world of material science with numerous superlatives to its character. Graphene is the first 2D atomic crystal material [1, 2] in the world and also well-known as wonder material, is compatible for numerous applications which was primarily isolated in 2004 . Graphene is a one-atom-thick planar sheet made up of sp2-bonded carbon atoms tightly organized in a crystal honeycomb lattice, and it is the lightest and strongest substance ever recorded in the universe. It’s tougher than steel and can stop a bullet, but it’s also weirdly elastic, which means it’s both flexible and tough. Even at room temperature, its charge carriers show great inherent mobility, have zero effective mass, and can traverse millions of interatomic lengths without scattering .
Graphene can uphold present intensities six orders of enormity which is superior than that of copper , shows higher thermal conductivity  and impermeability, high electron mobility  and rigidity, and also resolves brittleness and ductility which is mentioned as incompatible qualities of materials . Because of the remarkable properties of graphene, it has been widely integrated into polymers, and a large number of experimental research has shown that incorporating graphene can improve the mechanical, electrical, optical, and thermal properties of nanocomposites, and it has attracted a lot of attention in the scientific community. The ability of graphene to achieve various improved features when combined with a host matrix reveals prospective uses. Graphene’s incredible capabilities have made it a “magic bullet” in the Composites sector .
Applications of graphene
Graphene and graphene-based materials due to their improved mechanical, electrical, thermal, tribological, as well as gas barrier properties are significantly used in a wide variety of applications including automotive, aerospace, biomedical, sensors, energy storage, etc. In this article, let’s learn about the application of graphene in sensor and energy storage.
Application of graphene in Sensors
Graphene’s high electrical conductivity is the primary reason for its usage in sensing technologies. A sensor detects differences in physical properties and turns them into quantifiable signal responses. A homogeneous dispersed graphene micro ripple was formed by attaching graphene strips to a pre-strained polymer substrate to build exceptionally sensitive sensors. In this process the sensor works based on the increase in the sheet resistance of graphene caused by the electron scattering that occurs at the ripples when the physical change happened because of disruption of ripples.
Monolayer graphene gets tremendous use in sensing gases and biomolecules  where the charge transfer between the adsorbed molecule and the chemical response regulated by graphene. Graphene-based materials–based biosensors have the benefit of higher sensitivity, with selectivity, speedy response time, permanency, and a low limit of detection (LOD) .The monitoring, informing, and prompt detection of toxic gases  become more prevalent to avoid or lessen accidents that involve poisoning and blasts.
Generally, the conductivity of graphene is metallic, and it exhibits low Johnson noise even in the limit of no charge carriers . The crystal defects appear in graphene structure make certain a low level of excess noise caused by their thermal switching. All these qualities amplify the signal to- noise ratio to detect changes in a local intensity by less than one electron charge at room temperature and rise the sensitivity to its ultimate limit and detect individual . Graphene has been shown to be a viable choice for detecting a wide range of target compounds. Using a mix of nanofiller and conducting polymers, sensors may be made. As a result, due to their 2D (atom-thick) conjugated structures, higher conductivity, and large specific surface areas, functionalized graphene or graphene-based materials can be used for a variety of sensor applications (e.g., temperature, biomolecules, pressure, pH, and strain sensors) [14, 15]. In addition, graphene-based polymer composite films have superior electrocatalytic activity , enhanced electrochemical stability, and faster charge transfer between the components . Moreover, graphene is also impermeable to gaseous molecules, thus paving the way for gas sensor applications .
Graphene’s capacity to detect biomolecules is one of its many important sensing characteristics. Electrodes for heart rate monitoring, strain sensors, alcohol sensors, glucose sensors, CO2 and NO2 gas sensors, and temperature sensors have all been developed using graphene-based e-textiles . The GO-based fabric has been used as wearable gas and alcohol vapors sensors and exhibited promising results . Graphene-based materials biosensors benefit due to higher sensitivity, speedy response time, permanency, and a low limit of detection (LOD). Lu et al. reported  for the first time, a graphene-based biosensor with a dye labeled act as a DNA probe that could be found and quenched by GO resulting from the fluorescent energy transfer between the dye and GO. In addition, Jang et al. demonstrated the sensitive charge carrier modulation of chemically tailored graphene has permitted to biodevices development which can detect a single bacterium/sense DNA . The application of graphene as a nano-scaffold in catalysis, chemical/biosensing, imaging, and drug delivery will need research into the surface of graphene and the interaction of chemicals and biomolecules at the graphene interface .
Application of graphene in Energy Storage
The use of graphene-based materials for energy storage is gaining a lot of traction these days. Lithium-based batteries are the most widely used rechargeable electrochemical energy storage systems. These batteries are required to power portable electronic devices such as smartphones, laptops, computers, and other devices that can store electricity generated from renewable sources, as well as to be a key component in emerging hybrid electric gadgets. New materials chemistry is required to address future difficulties and achieve growth in energy and power density of energy storage. In energy storage applications, graphene-based nanocomposites can replace standard rechargeable lithium batteries while retaining better energy and power density [21, 22].
In recent decades, much research has been conducted on the incorporation of Li+ ions into the lattice of graphite, and electrochemical energy storage capacity in graphene-based devices is receiving a lot of attention . Having low density of lithium in graphite leads to the reasonably low specific capacity of graphite, 372 mA h g-1  by utilizing individual graphene sheets, the storage capacity limit is 744 mA h g-1 when both sides of the graphene sheet lithium is stored, and creating LiC3 structures. Supercapacitors made of graphene can be charged quickly, store a large amount of power, and are lightweight. The graphene-based lithium-ion batteries might be employed in higher-energy applications like electric cars, cell phones, laptops, and tablet computers, but at a smaller and lighter size.
Graphene and graphene-based materials thanks to their outstanding physicochemical properties opened up the new horizon of possibilities in the material science and engineering discipline. Graphene is considered to be an ideal candidate for next generation materials due to its outstanding properties. At present graphene along with other nanomaterials are significantly being used in almost every sphere of our lives.