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What are the new materials for lithium batteries?

2020-12-31 09:22

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1. New high-entropy energy storage materials for new materials for lithium batteries


A new type of high-entropy material suitable for energy storage applications proposed by the Karlsruhe Institute of Technology in Germany. Researchers use multi-cation transition metal-based high-entropy oxide as the precursor, LiF or NaCl as the reactant, and use simple mechanochemical methods. , Preparation of polyanionic and polycationic compounds to generate lithiated or sodiumized materials, and successfully synthesized a fluorooxy cathode active material with a rock salt structure, which is suitable for the next generation of lithium battery applications.


The advantage of this new type of lithium battery material is that it has stable entropy, exhibits stronger lithium storage performance, changes the constituent elements of traditional lithium batteries, improves cycle performance, and can reduce the use of toxic and expensive elements in the battery's positive electrode.



2. Layered oxides of new materials for lithium batteries


According to industry media reports, domestic researchers have made progress in the field of layered metal oxides. Researchers have found that the diffusion of oxygen in layered oxides is far easier than people imagined, and the diffusion and loss of oxygen ions during battery cycling This resulted in the formation of a large number of nano-sized bubbles inside the material, and at the same time caused a phase change in the crystal structure of the material. The results have been published in "Nature Nanotechnology".


This new type of lithium battery material has changed people's understanding of the generation and diffusion of oxygen ions in layered metal oxides, and has provided an important research foundation for the stability of lithium battery cathode materials.


3. Multilayer silicon/carbon composite structure of new materials for lithium batteries


The State Key Laboratory of Metal Material Strength of Xi'an Jiaotong University cooperated with Suzhou Research Institute and Nano Institute of Xi'an Jiaotong University to prepare a Cu conductive additive and carbon nanotube-reinforced multilayer silicon/carbon composite structure based on an in-situ controllable gelation process. The multilayer structure and the carbon nanotube toughened carbon matrix can effectively release the huge stress caused by the volume change of the silicon anode during charge and discharge. The introduction of Cu conductive additives improves the conductivity of the composite material. The results have been published in "American Chemical Society Nano".


Breakthrough point: The composite electrode has a specific capacity of 1500 mAh·g-1 after 900 cycles at a high current density of 1A·g-1; it exhibits 1035mAh·g cycling at a high current density of 4A·g-1 The specific capacity of -1 fully indicates that the electrode material still maintains excellent structural stability during the huge volume change of silicon particles. The research work solved the bottleneck problem of the volume effect of silicon negative electrode through the ingenious design of microstructure and interface structure, and is expected to provide an important reference for the development and application of a new generation of high-performance lithium ion silicon anode.


4. Cyclohexanone, a new material for lithium batteries


The team of Chen Jun, an academician of the Chinese Academy of Sciences and professor of the School of Chemistry of Nankai University, designed and synthesized an organic cathode material for lithium-ion batteries with ultra-high capacity-cyclohexanone, with a discharge specific capacity of 902mAhg-1. In addition, due to the low solubility of cyclohexanone in ionic liquids with high polarity, it has better cycle performance in ionic liquid-based electrolytes, and the assembled battery exhibits the characteristics of high capacity and long cycle life. The results have been published in "Germany Applied Chemistry".


This type of organic cathode material exhibits the highest capacity value currently reported for lithium-ion batteries, breaking the world record for the capacity of organic cathode materials for lithium-ion batteries. This work provides a new idea for the design, preparation and battery application of high-capacity organic electrode materials. Lithium-ion batteries with cyclohexanone as the positive electrode can achieve the advantages of higher battery capacity and longer life, providing support for future applications in electric vehicles, energy storage grids and other fields.

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5. Graphite + halogen conversion intercalation chemistry of new materials for lithium batteries


The University of Maryland introduced halogen conversion intercalation chemistry in graphite, innovatively developed a composite electrode, and combined this cathode with a passivated graphite anode to create a lithium-ion water-based full battery that can reach 4V with an energy density of 460 Wh/kg. The Coulomb efficiency is about 100%. The battery is based on the negative ion conversion-intercalation mechanism, combined with the conversion reaction of high energy density, has excellent reversibility of intercalation, and improves the safety of water-based batteries.


Breakthrough point: This battery is fundamentally different from the "dual ion" battery. The dual-ion battery inserts complex anions into graphite reversibly at low packing density, and stable anions do not undergo redox reactions, resulting in a capacity of less than 120mAh/g. The energy density of the new full battery is about 460 Wh/kg, which is higher than that of the most advanced non-aqueous liquid lithium-ion battery (after taking into account the electrolyte quality, its energy density can still reach 304 Wh/kg).


6. Boron nitride nano-coating for new materials for lithium batteries


Columbia University stabilized the electrolyte in lithium-ion batteries by implanting boron nitride (BN) nano-coatings, thereby reducing the risk of battery short circuits.


Breakthrough: The liquid electrolyte inside the lithium-ion battery is highly flammable, and there is a risk of short circuit and fire. However, the 5 to 10 nanometer boron nitride (BN) nano film can be used as a protective layer to isolate the metal lithium and the electrolyte. For electrical contact, boron nitride (BN) nano-film is chemically and mechanically stable to lithium, and has a high level of electronic insulation, so it can improve the safety of lithium-ion batteries to a greater extent.


7. Amorphous Al2O3 coating for new battery materials


Researchers at Hanyang University in South Korea have used amorphous Al2O3 to improve the surface of graphite. The amorphous Al2O3 coating has greatly improved the wettability of graphite and other battery materials and battery separators. Researchers used LiCoO2 cathodes and Al2O3 coated graphite anodes to carry out pure cell tests. Tests have shown that the introduction of amorphous Al2O3 can improve the charging performance of graphite anode materials. The results have been published in Energy Magazine.


At a high charging rate of 4000mA/g, the reversible capacity of surface-modified graphite is about 337.1?mAh/g, of which Al2O3 accounts for 1% by weight. When the electric strength is 100?mA/g, the corresponding capacitance The possession is about 97.2%. Researchers predict that the coating increases the electrolyte permeability of the entire surface area of the graphite electrode, thereby improving the fast charging performance of the graphite anode material. This achievement improves the fast charging performance of graphite anode materials for lithium-ion batteries.


8. Porous silicon-based composite anode (ASD-SiOC) for new lithium battery materials


The research team of Researcher Yang Jianping and the research team of Professor Jiang Wan from the School of Materials Science and Engineering of Donghua University have made important progress in the field of silicon-based lithium-ion batteries. The research team selected a phenyl bridged organosilicon precursor and used a two-step reaction of the sol-gel method and high-temperature calcination to prepare a new porous silicon-based composite anode (ASD-SiOC) that exhibits excellent cycle stability And structural stability. The results have been published in "Germany Applied Chemistry".


This new design has many advantages: the active matrix SiOx unit and carbon can be combined at the atomic scale; the carbon three-dimensional network effectively improves the conductivity of the material; the porous structure not only buffers the volume expansion, but also accelerates the transmission of lithium ions; In the subsequent cycle process, the ASD-SiOC anode can be transformed into a more stable composite structure, which can achieve high coulombic efficiency. This study shows that the carbon distribution plays a very important role in maintaining the structure and performance stability of the composite anode material.


Silicon Nanoparticles of New Materials for Lithium Battery


The team of chemist Briak at the University of Alberta in Canada found that molding silicon into nano-sized particles helps prevent it from breaking. Researchers tested four different sizes of silicon nanoparticles and found that the smallest particles (only one part of a meter in diameter) exhibited the best long-term stability after multiple charge and discharge cycles. The results have been published in "Materials Chemistry".


This achievement overcomes the limitations of using silicon in lithium-ion batteries. This discovery may result in a new generation of batteries with 10 times the capacity of current lithium-ion batteries, a critical step towards the manufacture of a new generation of silicon-based lithium-ion batteries. The research has broad application prospects, especially in the field of electric vehicles, which can make it travel farther, charge faster, and battery weight is lighter.