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Electronic information age, so that the mobile power needs are growing rapidly. As the lithium-ion battery Laptop Battery with high voltage, an important advantage of high capacity and long cycle life, safety performance is good, so that the portable electronic devices, electric vehicles, space technology, defense industry, and many have broad application prospects, becoming the last few years of extensive public attention in research focus. The mechanism of lithium-ion battery general analysis that the lithium-ion battery as a chemical power source, refer to two separate and de-embedding can be reversibly lithium intercalation compounds as positive and negative ion secondary battery constituted. When the battery is charging, the lithium-ion from the cathode in the de-embedded, embedded in the cathode, discharge the contrary. Lithium-ion battery is physics, materials science and chemistry of the crystallization of interdisciplinary research. Lithium-ion batteries involved in the physical mechanism, is currently being embedded in solid-state physics to explain the physical, the FRU 92P1139 embedding (intercalation) is movable object particles (molecules, atoms, ions) reversible embedded in the main body with the right size of the lattice The network space point. Electron transport lithium-ion battery cathode and anode materials are mixed ionic and electronic conductor embedded compound. Electronics can only be positive and negative material movement [4] [5] [6]. Embedded in a wide range of known compounds, object particles can be molecules, atoms or ions. In the embedded ions, requested by the main structure for charge compensation in order to maintain electrical neutrality. Charge compensation can be the main material can be achieved with changes in the structure, electrical conductivity before and after the embedded subject to change. Lithium-ion battery electrode materials can exist stably in the air is closely related with this feature. Intercalation compound only to meet the structural changes in reversible and are able to change the structure in order to compensate for the charge, as lithium-ion battery electrode materials.
Control the performance of lithium-ion batteries key material - Battery FRU 92P1141 Chiang Kai-shek negative active material is the key to this technology, it is the consensus of the researchers at home and abroad.
A cathode material performance and the general preparation method
Positive characterization of ion transport in the nature of the important parameter is the chemical diffusion coefficient, usually, the positive active material in lithium-ion diffusion coefficients are relatively low. Cathode materials for lithium insertion into or from the working-class de-embedded material, accompanied by changes in crystal phase. Therefore, the lithium-ion batteries require a very thin film electrodes, usually tens of microns in order of magnitude. Cathode Material Lithium compounds are lithium-ion battery Lithium-ion temporary storage containers. In order to obtain a high single battery voltage, tend to choose high electrical potential of the lithium intercalation compounds. Cathode material should be met:
1) In the required charge-discharge potential within the electrolyte solution has the electrochemical compatibility;
2) moderate kinetics of electrode process;
3) a high degree of reversibility;
4) full of state of lithium in the air stability.
The study focused on layered LiMO2 hot and FRU 92P1137 spinel-type structure of compounds and composite LiM2O4 two kinds of M (M is Co, Ni, Mn, V and other transition metal ions) is similar to the electrode materials. As a lithium-ion battery cathode material, Li + ions in the process of de-embedding and embedding structural changes in the extent and reversibility determine the stability of the battery charge and discharge of repetition. Preparation of cathode material, its material properties and synthesis of process conditions will have an impact on the final structure. A variety of promising cathode material, there is the use of the cycle of decay in capacitance, which is a research priority. Have been commercialized cathode materials Li1-xCoO2 (0 <x <0.8), Li1-xNiO2 (0 <x <0.8), LiMnO2 [7] [8]. Them as a cathode material for lithium-ion batteries have their own advantages and disadvantages. Lithium cobalt oxide as cathode of lithium-ion battery has a high open circuit voltage than the energy of large, long cycle life, fast charge and discharge, etc., but the poor security; lithium nickel oxide lithium cobalt oxide than the low-cost, performance and lithium cobalt oxide equivalent lithium intercalation has more excellent performance, but the preparation difficult; and lithium manganese oxide are much cheaper, preparation is relatively easy, and its resistance to overcharge safety performance is good, but its lithium insertion capacity is low, and when the spinel structure does not charge and 02K6651 discharge stable. From the application perspective, to find abundant resources, cheap and pollution-free, but also in over charging voltage control and circuit protection requirements of the advantages of low-, high-performance cathode materials will be a lithium-ion battery cathode material research key. It has been reported LiVO2 abroad can also form a layered compounds can be used as positive electrode material [9]. Be seen from these reports, although the chemical composition of the same electrode materials, but the preparation process changes, its properties change more. The successful commercialization of technology in the preparation of the electrode material has its own unique, which is the gap between the current study is located. Advantages and disadvantages of various preparation methods are listed below.
1) solid-phase method generally used in lithium carbonate and other lithium salts and cobalt or nickel compounds, lapping compounds, after mixing to sintering reaction [10]. Advantage of this method is to process simple and easy to get raw materials belonging to the early development of lithium-ion battery development and production has been extensively studied approach, the more mature foreign technology; disadvantage is that the prepared cathode materials for electric capacity is limited, poor mixing of raw materials, preparation of materials performance, stability, good, quality, consistency between batches and the batch difference.
2) The complex method using 02K6928 organic complex preparation containing the first lithium-ion and cobalt or vanadium ion complex precursor, and then sintering. This method has the advantage of molecular-scale mixing, material uniformity and performance, good stability, cathode materials, high capacitance compared to solid-state method, and foreign has been testing lithium-ion batteries used for the industrialization of methods, technologies not mature, yet few reported.
3) sol-gel method using the last century, 70 years since the development of
Preparation of ultrafine particles to the method of preparation of cathode material, the method has the advantages of the complex law, but also prepared the capacitance of the electrode materials have a greater increase being at home and abroad belong to the rapid development of methods. The disadvantage is high cost of technology is a development stage [11].
4) ion exchange process such as Armstrong prepared by using ion-exchange LiMnO2, won the reversible discharge capacity of 270mA · h / g high-value, this method for studying the new hot spot, which has the electrode system, stable performance, high capacity electrical characteristics of . However, re-crystallization process involves evaporation of solution and time-consuming 02K6620 steps such as license fees, there is a considerable distance away from practical use.
Cathode materials research literature can be seen from abroad, its power capacity to an annual 30 ~ 50mA · h / g at the rate of growth and development tend to become smaller and smaller-scale micro-structure, while increasing power capacity of lithium intercalation compounds and raw materials to the nano-scale advance, on the structure of lithium intercalation compounds, theoretical research has made some progress, but its development in the theory is still evolving. Trouble in this area increases the capacity of lithium battery power and recycling capacity fade problem, researchers have proposed to add other components to overcome the method [12] [13] [14] [15] [16] [17]. But for now, these methods have not thoroughly studied the theory of the 02K7039 mechanism, leading Japanese scholars Yoshio.Nishi that in the past decade, little substantive progress in this field [1], an urgent need for further study.