Graphene has been highly valued in the fields of chemistry, physics, materials and energy due to its unique electrical, mechanical, thermal, optical properties and high specific surface area. It has broad application prospects and is recognized as the “revolutionary material” of the 21st century. The main application areas of graphene: First, the field of energy storage. Graphene can be used to manufacture supercapacitors and super lithium batteries. The second is the field of optoelectronic devices. Graphene can be used to manufacture solar cells, transistors, computer chips, touch screens and electronic paper. The third is the field of materials. Graphene can be used as a new additive to make new coatings and antistatic materials. The fourth is the field of biomedicine. Graphene has good barrier properties and biocompatibility, so it can be used for drug delivery, biological diagnosis, fluorescence imaging and biological monitoring. The fifth is the field of heat dissipation. Graphene heat-dissipating films can be widely used in ultra-thin and high-power electronic products, such as smartphone,ipad and LCD TV.
Graphene lithium-ion battery
The graphene material is only used in the electrode of the lithium-ion battery. In theory, graphene electrodes may have twice the specific capacity of graphite. In addition, if a mixture of graphene and carbon black is added as a conductive additive to the lithium battery, the internal resistance of the battery can be effectively reduced, the battery rate charging and discharging performance and the cycle life can be improved. Graphene exists mainly in three forms in lithium batteries: conductive additives, electrode composites, and directly as a negative electrode material.
Graphene fuel cell
A fuel cell is a power generation device that directly converts chemical energy existing in a fuel and an oxidant into electrical energy. Graphene is beneficial for solving technical problems and cost problems in fuel cells. The transport properties of graphene-based membrane materials can be expected to solve the problem of penetration of the core component "proton conductive membrane" in fuel cells. Meanwhile, the nitrogen-doped graphene catalyst can significantly reduce the cost of fuel cell.
Graphene paper battery
Graphene oxide can be made into graphene paper. Graphene paper can function as a proton conductor, and a battery made of graphene paper has a good initial capacity. The incorporation of graphene can increase the specific capacity and the utilization rate of the active material of the battery by more than 10%. Graphene is added to the negative electrode of the battery to improve the high-rate discharge performance and greatly prolong the cycle life. The negative electrode plate with graphene has a high porosity of more than 70% .
Graphene supercapacitor
Supercapacitor is an electrochemical energy storage device between traditional capacitors and secondary batteries. It has the advantages of high power density, fast charge and discharge, high cycle life, no pollution, etc. However, supercapacitors are currently restricted by electrode materials, and the energy density is generally lower than 20 wh/kg. Graphene itself has an ultra-large specific surface area (2600 m2/g). It can be used in supercapacitor electrodes to significantly increase the energy storage density. Its energy storage density is close to that of lead-acid batteries, which is an ideal electrode material for supercapacitors.
Graphene solar cell
The graphene has a high transmittance (97.3% for a single layer) and a low sheet resistance. The use of graphene can improve the photoelectric conversion efficiency and can be used as a receptor material in solar cells. Graphene can be combined with organic polymer materials to form a large interface, which can increase the diffusion rate of excitons and carrier mobility in the battery, and can eliminate secondary aggregation due to the destruction of the charge transport path. In addition, graphene materials are also applied to the photoanodes of various types of solar cells such as dye-sensitized solar cells and perovskite solar cells. Depositing the graphene film on the silicon surface is beneficial to the surface passivation, heterojunction formation of the silicon cell, and effectively improves the photoelectric conversion efficiency of the battery.
Storage of hydrogen energy by graphene
It is well known that the amount of hydrogen adsorbed by a material is proportional to its specific surface area. Graphene has the advantages of light weight, high chemical stability and high specific surface area, making it the best candidate for hydrogen storage materials. The Greek university has designed a new 3D carbon material with an adjustable pore size. When this new carbon material is doped with lithium atoms, the graphene column can store up to 611% of hydrogen.
Graphene functional coating
Graphene's high specific surface area, high thermal conductivity, stable chemical properties and excellent mechanical properties make it an important "condiment" for next-generation coatings, rubber and plastics, which can enhance the performance of traditional products. And it has little impact on the original production process and cost, which makes graphene the focus of a new generation of coatings. Graphene can be used to produce pure graphene coatings and graphene composite coatings, which can significantly improve the performance of polymers. Therefore, graphene composite coating has become an important application research subject in coating field.
Graphene heat dissipation coating
The thinning of electronic products has become a trend. As the performance of the product increases, the high-power processing chip brings faster processing speed and lower power consumption, but at the same time puts higher requirements on the heat dissipation of the smart terminal. Carbon materials represented by graphene heat-dissipating films have become the most promising heat-conducting materials due to their high thermal conductivity, low density, low thermal expansion coefficient and good high-temperature mechanical properties. Graphene heat-dissipating coatings have great application prospects and can be widely used in the heat dissipation of air conditioners, LED lamps, high-power chips and so on.
Graphene conductive coating
Conductive coatings are special functional coatings that have been rapidly developed along with the development of modern science and technology. They have been widely used in the fields of static dissipation, electromagnetic shielding, and electronic packaging. Graphene can better realize the function of conductive coatings due to its high electron mobility and excellent electrical properties. Moreover, because of its excellent mechanical properties and thermal properties, graphene has made this new conductive coating more durable and more suitable for complex environments. It is an excellent conductive coating additive.
