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2017 lithium industry will continue to heat up, and what is the most popular lithium material? This article specifically for everyone to count the 2017 most popular lithium new materials
1, graphene
  The last two years, graphene-related "industry" in the country is also in full swing. Graphene in the lithium industry is more concerned about the application. What is graphene? Graphene (Graphene) is a carbon atom to sp2 hybrid orbit into a hexagonal honeycomb lattice plane film, only one carbon atom thickness of the two-dimensional material. Graphene is currently the world's thinnest but also the most hard nano-materials, it is almost completely transparent only absorb 2.3% of the light; thermal conductivity up to 5300W / m ˙ K, higher than carbon nanotubes and diamonds, the electron mobility at room temperature 15000cm2 / V ˙s, and higher than the carbon nanotubes or silicon crystals, and resistivity of only about 10-8 俜 m, lower than copper or silver, the world's smallest resistivity of the material. The graphene mainly has the following production methods: mechanical stripping method, chemical vapor deposition (CVD), oxidation-reduction method, solvent stripping method, solvent heat method, high temperature reduction, light reduction, epitaxial crystal growth method, microwave method, arc Law, electrochemical law and so on.
The term "graphene battery" is hot. At present, almost all of the commercial lithium-ion batteries are made of graphite anode material. Previously, Huawei announced in the field of lithium-ion battery to achieve a major breakthrough in research, introduced the industry's first high-temperature long-life graphene lithium-ion battery. Experimental results show that the new high-temperature technology based on graphene can increase the use of lithium-ion battery temperature limit 10, the life of ordinary lithium-ion battery is 2 times. It is foreseeable that 2017 graphene will continue to be a popular material for the lithium industry.
2, silicon negative
With the rapid development of electronic technology, as well as the rapid popularization of electric vehicles, the market demand for high specific energy lithium-ion battery more and more strong, while the traditional graphite material theoretical capacity of only 372mAh / g, far from high The demand for lithium-ion batteries, under the stimulation of huge market demand, a variety of new negative materials have begun to appear, such as silicon-based anode materials, tin-based anode materials, nitrogen-doped porous graphite materials and transition metal sulfide negative ( Such as MoS2), etc., in this many new negative materials, the current technology is more mature for the silicon-based anode material, has now achieved small-scale commercial applications.
In fact, the high voltage, polymer, silicon negative of these three are lithium batteries, silicon anode is only a new technology, most of the current lithium batteries are carbon-based materials as the negative, but because of this carbon The reversible capacity of the negative electrode of the material is only 372mAh / g, which seriously limits the future development of lithium ion battery, so the need to develop the next generation of lithium ion battery anode material. In the course of the study, the researchers found that a silicon element (Li22Si5) capacity of 4200mAh / g, is the development of high-capacity battery with excellent material. And the use of such a negative material made of the battery in the course of the use of almost no capacity attenuation, more conducive to improving the battery life. Coupled with silicon on the earth is rich in reserves, low cost, and thus is a very promising lithium-ion battery anode material.
3, aluminum foil charcoal
Carbon-coated aluminum foil is a new type of battery cathode substrate, compared to the traditional aluminum foil, coated with aluminum foil has good conductivity and resistance to small, strong mechanical properties and toughness, etc., to avoid shortening of the burr, improve the adhesion of electrode materials, Large battery discharge capacity and extend the life of lithium-ion battery.
Chinese Academy of Sciences, Shenzhen Advanced Technology Research Institute of Xuefeng Tong, who developed a carbon-based aluminum foil negative double-ion battery, which not only as a collector, but also as a negative electrode material. Compared with the graphite material, Al has a higher theoretical specific capacity, when the formation of LiAl structure, the specific capacity can reach 993mAh / g, the formation of Li9Al4 material, the specific capacity of 2235mAh / g, the voltage platform is only 0.19-0.45V vs Li + / Li, compared to the silicon material has a smaller volume expansion, the formation of Li9Al4, the volume expansion is only 97%, and Al material also has good conductivity, easy processing and low cost advantages, but Al negative current Still need to improve its cycle life.
Carbon coated porous aluminum anode preparation process is relatively simple, first aluminum foil by electrolysis method of corrosion treatment, and then coated with a layer of PAN material on its surface, after low temperature curing and high temperature carbonation, the aluminum foil can be formed in a layer Carbon layer, can repeatedly repeat the PAN process to improve the carbon content, the study found that a carbon-coated carbon content of about 1.5%, twice carbon coated carbon content of about 2.8%, three carbon coated carbon content of about 4 %.
4, ceramic mixed plastic membrane
As the lithium battery material is an important factor affecting its safety performance, in order to ensure the safety of lithium batteries, the choice of more secure diaphragm to become one of the many companies to consider the direction.
Ceramic diaphragm, is the nano-ceramic particles coated on the diaphragm. Its role is to improve the diaphragm heat shrinkage, to prevent the diaphragm caused by a large area short circuit. In addition, the ceramic thermal conductivity is low, to prevent the battery in some of the thermal control point to expand the formation of the overall thermal runaway. Generally high temperature at about 200 ℃. Ceramic-coated markets are mainly high-voltage batteries and power batteries. The development direction of two: First, coated with alumina, LG as the representative, using dip coating; Second, the surface to do a layer of aramid, represented by the Japanese Teijin.
The future of ceramic diaphragm will have a wide range of applications, it is to solve the problem of lithium battery safety is an important means, but also the future development of lithium battery diaphragm in one direction.
5, aramid coated diaphragm
With the lithium battery in the energy storage, new energy vehicles, electric bicycles to promote the rapid growth of the diaphragm market, which ternary material penetration of ceramic coating on the increase in demand for diaphragm. For the diaphragm, whether it is PI, TPX, aramid and other high temperature resin matrix membrane preparation, or non-woven fabrics and paper diaphragms in some special areas of research and development, in the future electrostatic spinning technology will replace the existing diaphragm technology. Aramid coated diaphragm suction, liquid retention performance, can enhance the capacity, more light, without affecting the premise of security, to create a more thin to meet the small, miniature high-capacity battery. Ion conductivity of the new material diaphragm. In addition, aramid coated diaphragm to solve the high temperature is not deformed, to avoid the occurrence of short circuit, low self-discharge, can reduce the short circuit caused by the capacity loss, high rate performance, electrolyte infiltration performance and improve the cycle performance.
6, CNT
CNT's full name is Carbon Nanotube. Chinese name is carbon nanotubes, and diamond, graphite, fullerene, is a kind of carbon allotrope. It is a tubular carbon molecule, each carbon atom on the tube to take sp2 hybrid, with carbon-carbon σ bond between each other to form a hexagonal honeycomb structure as a carbon nanotube skeleton.
Carbon nanotubes were discovered in January 1991 by physicists from Nippon Tsukuba NEC Labs, Nippon Shimizu, using high-resolution transmission electron microscopy (TEM) to produce carbon fibers from arcs. It is a tubular carbon molecule, each carbon atom on the tube to take sp2 hybrid, with carbon-carbon σ bond between each other to form a hexagonal honeycomb structure as a carbon nanotube skeleton. A pair of p-electrons that do not participate in hybridization on each carbon atom form a conjugated π-electron cloud that spans the entire carbon nanotube. According to the number of layers of the tube, divided into single-walled carbon nanotubes and multi-walled carbon nanotubes. The radius of the tube is very fine, only nano-scale, tens of thousands of carbon nanotubes and up and only one hair width, the name of carbon nanotubes also come. And in the axial can be up to tens to hundreds of microns.
As a high-quality nanomaterials, carbon nanotubes have the same electrical properties as the graphite sheet structure. Carbon nanotubes have extraordinary strength, thermal conductivity, magnetoresistance, and the nature of the structure will change with the changes can be from the insulator into a semiconductor, from the semiconductor into a metal; metal conductive carbon nanotubes through the magnetic flux is quantum Of the performance of the Akhanov - Pum effect (AB effect).
7, high voltage cathode
Lithium cathode material research and development has been one of the most important areas of lithium research, lithium cathode material in the end how to develop, but also we are very concerned about the topic. Improve the energy density, nothing more than two main ways to improve the electrode material capacity or improve the battery operating voltage. If the combination of high voltage and high capacity will be better, in fact, this is the current development of lithium battery cathode material mainstream, such as high voltage and high pressure lithium cobalt oxide, high voltage ternary materials, etc. The
8, NCA
Ternary material is nickel cobalt manganate Li (NiCoMn) O2, ternary composite cathode material precursor products, is nickel salt, cobalt salt, manganese salt as raw material, which the proportion of nickel cobalt manganese can be adjusted according to actual needs, three The material is made to have a high battery with respect to the lithium cobalt oxide battery.
At present, more and more electric vehicle vehicles using a ternary material battery, which is mainly due to ternary cathode material NCA It has the advantages of high energy density, long cycle life, low cost and favorable vehicle weight, which can effectively solve the problem of "last mile" of urban logistics, and thus the electric vehicle flow from lithium iron phosphate to ternary technology the trend of.