What is the world top lithium battery research team and research direction?

The battery technology in the development of society sustainable clean energy plays an important role.Compared to the traditional Ni-Mh batteries, lead-acid batteries,Lithium ion batteries with high energy density, no memory effect, low environmental pollution, etc are widely used in the field of energy storage and conversion.Now already as lithium-ion batteries power battery in electric vehicles, such as Tesla, BYD, has a great market share, is expected to 2020 global lithium ion battery the size of the market is expected to reach 450 billion yuan.

Lithium ion battery first developed by SONY of Japan in 1990.Traditional lithium-ion battery anode materials for lithium cobalt acid (LiCoO2), for graphite anode materials (C), esters as the electrolyte of rechargeable batteries.The battery electrode reaction is as follows:

Specific storage of the actual cobalt acid lithium materials, however, is only about 150 mAh/g, with low energy density of lithium ion battery capacity limits the monomer, only around 150 wh/kg.Using low energy density of lithium ion battery is regarded as the power battery of the car mileage making electric cars could have expected.Tesla's latest electric car ModelX, for example, the battery pack is consists of more than 7000 section 18650 lithium ion battery, weighs a ton.Heavy battery increases the weight of the car, reduce the mileage of the car, after a full charge range at about 400 kilometers.Therefore, development of high energy density lithium ion battery is particularly important.

At present, the study of high energy density lithium ion battery has been from beginning to the substantial development.The positive materials of the main areas of research focused on the battery, the cathode material.On the positive aspects of the main research, rich lithium battery anode materials of high sulfur nickel anode material and anode material.In the aspect of the cathode research mainly concentrated in the tin anode, silicon anode, and lithium metal anode.At present there are many team is dedicated to the study of the solid electrolyte, mainly to solve the problem of liquid electrolyte flammable security hidden danger.In addition in the research of lithium metal anode, introducing and using solid electrolyte can inhibit the growth of lithium dendrite.In this paper, combining with parts of the world's top lithium battery team to do a simple introduction, and elaborates the hot research direction of the industry.

JohnB．Goodenough

Dr Goodenough, professor at the university of Chicago in 1952 degree.Currently in the United States department of mechanical engineering, the university of Texas at Austin, Texas.Goodenough professor is a famous physicist, solid of the national academy of sciences, the academy of engineering, the royal society for foreign academicians.He is cobalt acid lithium, manganese acid lithium and lithium iron phosphate lithium-ion battery cathode material of the inventor, is also one of the founders of scientific basis, lithium-ion batteries is referred to as the "father" of lithium electricity industry.Professor Goodenough published more than 700 journal papers, published papers cited more than 46500 times.

In recent years, professor Goodenough continue in deep love of lithium ion batteries, sodium ion batteries, intensive research.At the same time also will own research field to expand to in the study of solid electrolyte of lithium ion batteries.Professor recently Goodenough and the solid electrolyte research papers published on Journal of American chemistry society (10.1021 / jacs.8 b03106).Goodenough professor think garnet solid electrolyte has the very high conductivity at room temperature, is suitable to the solid electrolyte of lithium battery using the ideal material.The study used a new strategy to improve the garnet LLTO (Li7La3Zr2O12) interface, which significantly reduces the lithium and the impedance of the interface of garnet, inhibit the formation of dendrite.Thus reducing the assembly of the Li/use Garnet/LiFePO4 and Li - S solid-state batteries of the electric potential, improve the efficiency of the coulomb and cycle stability, has wide application prospect.Through the use of solid electrolyte, lithium battery and lithium battery dendrite problem will be solved, use high capacity lithium as negative will have great development and application in the future.

Figure a, garnet LLZT and LLZT - C solid-state electrolyte of lithium battery.(10.1021 / jacs.8 b03106)

PeterG．Bruce

Professor Bruce is Oxford professor, department of big material. The Royal Academy of sciences, academy of engineering, the royal society for foreign academicians, published more than 400 journal papers, cumulative reference papers published more than 55100 times, H factor for 97.

The research direction of professor Bruce team focused on lithium air batteries, lithium-ion batteries, such as sodium ion battery direction.In terms of lithium ion battery cathode material, professor Bruce's research mainly involves LINixMn1 - xO2, xLi2MnO3?(1 -) x and LiMO2 Li2FeSiO4 research and development of the anode materials of high capacity, and its reaction mechanism research.

Recently, professor Bruce in sodium ion battery cathode material and made great breakthroughs in research and published in Nature ZiKan.(NatureChem.,10,288, 2018-2018) the article reported a P2 Na2/3 [Mg0.28 Mn0.72] O2 layered sodium ion battery cathode material, has nearly 170 mAh/g ratio capacity and nearly 2.Discharge voltage of 75 v.And that the stability of the high capacity from the material structure and the oxidation reduction of oxygen.When sodium ions out, low content of sodium to facilitate the formation of the structure of oxidation layer of O2.In addition of oxygen in the process of charging and discharging is REDOX reaction and contribution to the additional capacity.At the same time the introduction of the magnesium 2 + and inhibit the loss of oxygen.The work of Li-ion battery cathode material of the electricity and sodium oxygen oxidation reduction phenomenon and provides additional capacity provided further understanding, also provides the design materials from the structure and component, inhibit the loss of oxygen to implement the new way of high capacity anode material.

Figure 2, the P2 Na2/3 [Mg0.28 Mn0.72] O2 material structure diagram.(NatureChem.,10,288, 2018-2018)

Clare P．Grey

Clare P.Grey doctorate at the university of Oxford in 1991.Chemistry professor at the university of Cambridge, is now a member of the royal society, the state university of New York at stony brook part-time professor.Clare P.Grey has been more than 300 international publication published in the journal papers, cumulative reference papers published more than 23600 times, H factor for 78.Currently professor of Grey is Journal of American chemical society, Joule, accounts of chemical research international famous journals such as editors.

Professor Grey team's main research work is in the following direction: lithium-ion battery technology, sodium ion battery technology, a new type of lithium air batteries, magnesium ion battery and forward-looking research fields such as solid electrolyte.In recent years, professor Grey in lithium ion battery cathode material combined with the advantages of itself and characterization of advanced technology, in terms of material characterization and simulation was carried out by many studies.

Figure 3 shows the Grey, a professor at the study on the structure of spinel lithium transition metal oxide of the latest achievements (Chem.Mater.2018,30,817?829).Based on the research LiTIxMn2 - xO4 (0.2 x 1 or less or less.5) material, the use of NMR characterization techniques, such as combining the theory of DFT calculations, to study the influences of LTMO TI doped with different structure.Through the study found that the existence of TI doped makes the structure of the material changes with the change of TI content.In the X = 0.2, the Ti4 + and Mn3 + / 4 + LTMO show random distribution;In the X = 0.4 when are rich in Ti4 + and Mn4 + nonuniform lattice;In the x = 0.6 and 0.8 when single-phase solid solution formation;While at x = 1 present Li - Mn2 + tetrahedron and Li - Mn3 + / 4 + - Ti octahedron configuration.This work is to study the structural changes in the other battery electrode materials provided a reference basis.

FIG. 3, LiNi0.8 co0.15 al0.The Al of o2, Li, Ni, Co, spatial distribution map of O ions (Chem.Mater.2018,30,817?829).

Professor yi cui received a doctor's degree at Harvard University in 2002, is a professor at Stanford university department of materials science and engineering at present.Professor yi cui has published more than 700 papers in the journal international, and at the top of the international publication Nature and Science and its ZiKan published a total of 88 articles, published papers has cited more than 116300 times, 160 H factor.Is currently the international famous journals Nanoletter deputy editor, ACSappliedenergymaterial magazine editors, etc.

Professor yi cui team's research focuses on lithium ion battery silicon anode, get a lot of outstanding achievements in the field of silicon anode.At the same time, in recent years in terms of lithium metal anode, and lithium sulfur batteries made many excellent achievements.Especially in nearly three years in the study of lithium metal anode has made breakthrough progress, and in Science, Nature Nanotechnology, Nature Energy and other international top magazine published many articles in succession.

Figure 4 shows the latest research of professor yi cui large size silicon lithium alloy - graphene flexible electrode (Nature Nanotech.,12,993, 2017-999), the electrode is composed of active lithium silicon alloy nanoparticles, and the large size graphene layer evenly coated, has the good stability of the air.This structure effectively suppresses the volume expansion effect brought by the silicon alloying and inhibit the growth of the lithium dendrite, makes the electrode exhibited excellent cycle stability and the energy density of 500 WHKG - 1.Research and development of silicon lithium alloy anode is expected to be paired with sulfur cathode of high energy density of lithium sulfur - silicon alloy battery and a wide range of applications.

FIG. 4, silicon, lithium alloy - graphene flexible electrode electrochemical performance.(NatureNanotech.,12,993, 2017-2017)

LindaF．Nazar

LindaNazar professor in the university of Toronto in 1984, Ph.D.Is currently a professor of chemistry at the university of Waterloo in Canada, the Canadian national chief scientist, Canada's Royal Academy of sciences.Nazar professor has published more than 300 academic papers on international famous magazine, published papers has cited more than 34600 times, H factor for 89.Is currently the international famous journals Energy&EnvironmentScience, ACSCentralScience magazine editors, etc.

Nazar research direction of professor specializing in lithium battery and lithium air batteries, she is regarded as "the queen of lithium sulfur batteries.In recent years, the research direction of the team at the same time to expand to the lithium cathode protecting and inorganic solid electrolyte and a breakthrough.Figure 5 shows the recent Nazar, professor in the new strategy of lithium metal anode protection.(Joule, 2017,1,871-886), the work of adding electrolyte P2S5 in lithium metal in situ generated micron level, with a high ionic conductivity, good stability, solid electrolyte interface (SEI).The formation of the SEI fit closely in lithium metal surface, in the land of reciprocating lithium metal deposition in the process of pull out still remain stable, so as to realize long cycle life of lithium metal anode.In addition, the generated SEI closely contact with electrodes and curb the further reaction of lithium metal and the electrolyte, inhibiting the formation of dendrite at the same time.When paired with Li4Ti5O12 anode material, all the batteries in the 5 c electrical flow to achieve the cycle stability of the more than four hundred times.

Figure 5, the SEI formation process diagram, ion/electron transfer process diagram and ion concentration, electric field intensity, electric potential change curve.(Joule,,1,871 2017-2017)

summary

Combined with the current international research dynamic perspective, the traditional research of lithium ion battery material has been basically perfect and realize industrialization.Hot spot in research of silicon anode, tin anode and other anode materials are from infancy to the application stage, the present research paper also more attention in the loads of material, cycle life and practicability.Lithium ion battery research focus on the current international focus on lithium metal anode and solid-state electrolyte development.By developing the appropriate lithium protection means used lithium metal anode and through the use of solid-state electrolyte to solve the problems of other batteries (such as battery safety, polysulphide dissolved in lithium sulfur batteries, etc.) will be the future direction of research and development.And also from the traditional business of lithium ion battery cobalt acid lithium anode and graphite cathode to three yuan positive and silicon carbon negative, is expected to reach 300 wh/kg energy density can be.Later with the development of the silicon anode, high silicon nickel anode and the cathode battery will gradually appear application and can realize the energy density of 400 wh/kg.Is expected in 2030, with lithium protection and the rapid development of technology of solid electrolyte, long cycle life of lithium sulfur batteries will be put into lithium electricity market and the energy density of 500 wh/kg.The development of high energy density of lithium ion battery will significantly change the current energy storage system and greatly improve the storage capacity of electrochemical energy storage devices.

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