What are the advantages of graphene batteries?

Graphene: It is a kind of flat film with hexagonal honeycomb lattice composed of carbon atoms and sp2 hybrid orbitals. It is a two-dimensional material with the thickness of only one carbon atom. In 2004, physicists Andreheim and Konstantin Novoselov of the University of Manchester in the United Kingdom successfully separated graphene from graphite in an experiment, and proved that it can exist alone. Based on the groundbreaking experiment of the three-dimensional graphene material, they jointly won the 2010 Nobel Prize in Physics. Graphene is currently the thinnest but hardest nanomaterial in the world. It is almost completely transparent and only absorbs 2.3% of light. The thermal conductivity is as high as 5300W/mK, which is higher than carbon nanotubes and diamonds, and its electron mobility at room temperature Over 15000cm2/Vs, it is higher than carbon nanotubes or silicon crystals, and its resistivity is only about 10-6cm, which is lower than copper or silver. It is the smallest resistivity material in the world. Because of its extremely low resistivity and extremely fast electrons, it is expected to be used to develop a new generation of thinner and faster conducting electronic components or transistors. (Via Wikipedia) In simple terms, graphene is a single-layer graphite composed of carbon atoms. It is a flat film with a hexagonal honeycomb lattice with the thickness of only one carbon atom. It is obtained by thinning graphite layer by layer), which has very good thermal conductivity, electrical conductivity, light transmission, and has the characteristics of high strength, ultra-light and thin, and ultra-large specific surface area, so it is known as a super material. With its excellent characteristics in many aspects, graphene has a wide range of uses, and can be used in lithium battery electrode materials, thin film transistors, sensors, semiconductor devices, composite material preparation, and transparent display touch screens. The graphene battery mentioned above is one of its important uses. The true face of graphene batteries In recent years, there have been many and mixed news about graphene batteries on the Internet, and some media have even promoted graphene batteries as a disruptive revolution in lithium batteries. In fact, this is not the case. First of all, we have to be clear about a concept. The so-called graphene battery is not made of graphene materials for the entire battery, but graphene materials are used in the electrodes of the battery. In addition, graphite is the most commonly used negative electrode material in lithium batteries. When charging, Li is inserted between the graphite layers to form an intercalation compound. When Li is fully inserted, each graphite layer is embedded with a layer of Li, corresponding to the compound LiC6. The theoretical specific capacity is 372mAh/g. When each single-layer graphite is arranged in a chaotic manner, Li can be combined on both surfaces of the single-layer graphite, and the theoretical specific capacity is doubled, that is, 744mAh/g. Due to the defect sites of graphene, the edge of the sheet and the microporous structure formed by the accumulation of graphene, Li can be stored. In other words, in theory, graphene electrodes may have a specific capacity more than twice that of graphite. Note: The above picture shows the structure of composite electrode materials. In addition, if graphene and SnO2, Mn3O4, CuO and other low-conductivity cathode and anode nanomaterials, such as Li4Ti5O12, TiO2, LiFePO4, etc., are combined, it may be improved Cycle performance of lithium batteries. The Institute of Metal Research of the Chinese Academy of Sciences once published a paper in PNAS. The cathode material LiFePO4 and the anode material Li4Ti5O12 were compounded with graphene respectively to prepare LiFePO4-graphene/Li4Ti5O12-graphene as electrodes for flexible lithium batteries with high charge and discharge rates. Graphene As a pathway for lithium ions and electrons, it also serves as a conductive additive and current collector. If graphene and carbon black are mixed as a conductive additive and added to a lithium battery, it may be able to effectively reduce the internal resistance of the battery, improve the battery rate charge and discharge performance and cycle life, and the bending of the battery has no effect on the charge and discharge performance. However, Huawei and Qualcomm have previously implemented fast charging through high current density charging and discharging. The battery life loss is very large, although this shortcoming has been improved a lot in recent years. In contrast, the rapid charging of graphene batteries does not seem to reduce battery life, and it is more technically aesthetic. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous article: How do lithium batteries charge and discharge?