Summary: review the research and development of Cui Yi and his team together

Biography:

In 1998, he obtained a bachelor of science degree from the University of Science and Technology of China, and received a doctorate degree from Harvard University in 2002 (mentor Charles Lieber). During the period, he published articles including 4 science and 1 nature, and worked as a postdoctoral fellow at the University of California, Berkeley from 2003 to 2005. Research (mentor Paul Alivisatos), and joined Stanford University in 2005, is now a professor of materials science and engineering at Stanford University. He is currently Associate Editor of Nano Letters, Director of Bay Area Photovoltaics Consortium, and Director of Battery500 Consortium. Professor Yi Cui is a well-known materials scientist in the world today. His main research areas are energy storage, nano-microscopy technology, nano-environmental protection technology, nano-biotechnology, synthesis and manufacturing of advanced materials. , Multi-directional advancement is an important feature of Professor Cui Yi ’s research group. He has made many pioneering achievements in nanomaterials research. He has published nearly 400 research papers in high-level journals such as Science and Nature series Factor) 155, with a total citation of up to 100,000 times. Authorized more than 40 international patents and won a series of awards, including the 2017 Bravanik Young Scientist Award, 2015 MRS Kavli Distinguished Lectureship in Nanoscience, Resonate Award for Sustainability, 2014 Nano Energy Award, 2014 Blavatnik (Blavatnik) National Award Finalist Award, 2013 IUPCA (International Union of Theoretical and Applied Chemistry) New Materials and Synthesis Excellence Award, 2011 Harvard University Wilson Award, 2010 Sloan Research Fund, 2008 KAUST Research Award, 2008 ONR Young Inventor Award, 2007 MDV Innovation Award, etc., was selected as "Top 100 Young Inventors in the World" in 2004. Professor Yi Cui is also an entrepreneur. 9 years ago, he founded the first company Amprius (Amprius), producing silicon anode high-energy lithium batteries; in 2015, he and Nobel Prize winner and former US Secretary of Energy Professor Zhu Diwen co-founded 4CAir company, producing Haze filtering products. (Data collected on the Internet)

The following summarizes the research results of Cui Yi and his research team in recent years, so that everyone can fully understand the research progress.

presented paper:

1. Science Advances: stable interface design of 3D lithium anode

Under the leadership of Professor Cui Yi (corresponding author) of Stanford University in the United States , in collaboration with Bosch North American Research and Technology Center and the SLAC National Accelerator Laboratory in the United States , a new 3D electrode using ALD coated hollow carbon spheres (HCS) was designed and developed . The microporous carbon shell serves as a sturdy framework to limit electrochemical lithium deposition. Compared with previous research by the team, the thin ALD coating seals the micropores of the HCS to prevent the electrolyte from contacting lithium and inactivating the defective HCS surface. With this design, the liquid electrolyte only contacts the outer surface of ALD Al 2 O 3 / HCS and cannot penetrate the hollow sphere. Therefore, SEI is only formed outside the ALD-coated HCS during cycling. During lithium deposition, lithium ions penetrate the outer Al 2 O 3 / C shell and deposit inside the hollow sphere. Over 500 cycles have been achieved in the ether-based electrolyte, and the Coulomb efficiency is as high as 99%, which is better than most previous work under similar test conditions. Related achievements were published in Science Advances with the title " Engineering stable interfaces for three-dimensional lithium metal anodes " .

Literature link : Engineering stable interfaces for three-dimensional lithium metal anodes (Science Advances, 2018, DOI: 10.1126 / sciadv.aat5168)

2.Nat. Catalysis: Efficient electrocatalytic CO2 reduction on the three-phase interface

Under the leadership of Professor Cui Yi (corresponding author) at Stanford University in the United States , in collaboration with Professor Zhu Diwen , a gas diffusion design strategy that mimics the lungs of mammals was proposed: Simulated mammals transported O 2 from the air outside the human body to the body . The alveoli are about 200 μm in diameter, surrounded by ultrathin epithelial cell membranes (about 1 μm thick), and have high air permeability and low water permeability. During human pulmonary circulation, gas can quickly penetrate these multilayer membranes to exchange between the alveoli and capillaries, while the fluid remains separated. The hemoglobin in the red blood cells binds O 2 to act as a catalyst. The CO 2 released from the blood to outside the body follows the opposite path. Based on the working mechanism of alveoli, Professor Cui Yi ‘s team has developed a double-layer bag-like artificial alveolar structure, which is composed of a highly flexible ultra-thin nanoporous polyethylene (nanoPE) film with a very thin layer of gold nano-coated on one side Catalyst (~ 20nm). Utilizing the hydrophobicity of nano-polyethylene, this artificial alveolar structure can provide a large number of catalytically active sites at the three-phase interface and achieve local pH adjustment between the two-layer membranes. Thanks to this design, the electrochemical CO 2 RR is at -0.6V (vs. RHE), achieving an excellent CO generation Faraday efficiency (FE CO ) of ~ 92% and a CO generation current density of ~ 25.5mA cm ^-2 . Related achievements are entitled " Efficient electrocatalytic CO 2"Reduction on a three-phase interface " was published in Nat. Catalysis . The first author of the paper was Dr. Jun Li from Stanford University.

Literature link : Efficient electrocatalytic CO 2 reduction on a three-phase interface (Nat. Catalysis, 2018, DOI: 10.1038 / s41929-018-0108-3)

3.Adv. Mater: silica-aerogel reinforced composite polymer electrolyte with high ion conductivity and high modulus

Professor Yi Cui of Stanford University joint professor Reinhold H. Dauskardt developed a silica - reinforced airgel composite polymer electrolyte (CPE). In this design, aerogels have unique properties, with high elastic modulus, high porosity, and especially large internal surface area, which play a key role. By incorporating a strong SiO 2 aerogel backbone, the mechanical properties of the composite electrolyte are significantly improved, enabling the electrolyte to mechanically inhibit the growth of Li dendrites. The high porosity further promotes the occupation of a large amount of polymer electrolyte in the composite material, thereby achieving more efficient lithium ion conduction. Finally, the ultra-fine and uniformly distributed SiO 2 domain with a large internal surface area promotes a more pronounced Lewis acid-base interaction with the anions, and thus enables higher Li salt dissociation. The interconnected SiO 2 aerogel network with continuous high anion adsorption regions further improves ion conductivity. The related research result "A Silica-Aerogel-Reinforced Composite Polymer Electrolyte with High Ionic Conductivity and High Modulus" was published in Advanced Materials.

Literature link: " A Silica-Aerogel-Reinforced Composite Polymer Electrolyte with High Ionic Conductivity and High Modulus " ( Adv. Mater., 2018, DOI: 10.1002 / adma.201802661 )

4.Joule: Scalable lithium metal anode with improved mechanical and electrochemical cycle stability

American Stanford University ‘s Cui Yi (Corresponding author ) , who, for the first time to prepare a Li metal can stretch a stable mechanical and electrochemical properties of the cathode. Composed of highly elastic polymer rubber and "integrated" Li metal microdomains. During stretching, the rubber absorbs mechanical energy, while the electroactive Li region has no mechanical strain. Moreover, the entire electrode is made by simply winding a low-cost copper wire. Unlike traditional stretchable "lithium ion batteries", retractable lithium metal anodes are a key step in the development of new stretchable "lithium metal batteries" and are expected to increase the energy density of stretchable energy storage devices. Related achievements were published on Joule under the title of " Stretchable Lithium Metal Anode with Improved Mechanical and Electrochemical Cycling Stability " .

Literature link: Stretchable Lithium Metal Anode with Improved Mechanical and Electrochemical Cycling Stability (Joule, 2018, DOI: 10.1016 / j.joule.2018.06.003).

5.Nat. Energy: Manganese hydrogen battery with grid-scale energy storage potential

Cui Yi (corresponding author) of Stanford University and others have developed a new type of Mn-H secondary battery. In the two-electrode reaction, the positive electrode of the battery is soluble Mn ²⁺ and solid MnO 2 , and the negative electrode materials are circulating H 2 and H 2 O. Among them, H 2 and H 2 O are obtained through the catalytic reaction of hydrogen evolution and oxidation. The discharge voltage of this battery is ~ 1.3 V, and the capacity does not decay after 10,000 cycles. In 4 M MnSO 4 electrolyte, the mass energy density of the battery is ~ 139 Wh kg ^-1 and the bulk energy density is ~ 210 Wh l ^-1 . Mn-H battery is an energy storage device with low price, abundant raw materials and large-scale application potential. Related achievements were published on Nature Energy under the title of " A manganese–hydrogen battery with potential for grid-scale energy storage " .

Literature link: A manganese–hydrogen battery with potential for grid-scale energy storage (Nature Energy, 2018, DOI: 10.1038 / s41560-018-0147-7).

6.science: Fun with cryo-electron microscopy-revealing battery materials and interfacial atomic structure

On October 27, 2017, Beijing time , Science published an article entitled " Atomic structure of sensitive battery materials and interfaces revealed by cryo–electron microscopy " by Cui Yi (corresponding author) of Stanford University in the United States. After the award, another masterpiece of cryo-electron microscopy was applied. In theory, a single lithium metal atom and its interface can be decomposed on an atomic scale. Cui Yi‘s team realized the use of cryo-electron microscopy to observe the battery material and the atomic structure of the interface. It was observed that the dendrites in the carbonate-based electrolyte grew into (preferentially) or direction into single crystal nanowires. These growth directions may change, but no crystal defects are observed. In addition, the team also revealed different SEI nanostructures formed in different electrolytes. This work provides a simple method to preserve and image the original state of beam-sensitive cell materials on an atomic scale, revealing their detailed nanostructures. The relevant data observed from these experiments can achieve a complete understanding of the battery failure mechanism. Although this work uses Li metal as an example to prove the practicality of cryo-EM, this method may also be extended to other studies involving beam-sensitive materials such as lithiated silicon or sulfur.

Literature link: Atomic structure of sensitive battery materials and interfaces revealed by cryo–electron microscopy (Science, 2017, DOI: 10.1126 / science.aam6014)

7. Nature Energy: Breakthrough in high-reversible-capacity sodium ion batteries

Stanford University ‘s Professor Bao Zhenan and Professor Cui Yi (co-author) and other co reveals brown rose sodium (Na 2 C 6 O 6 ) The main limiting factor as sodium ion battery cathode materials. The study shows that Na 2 C 6 O 6 will undergo a phase transition between α-Na 2 C 6 O 6 and γ-Na 2 C 6 O 6 during charging and discharging . The reversibility of this phase change determines the Na 2 C 6 O 6 reversible capacity and long cycle stability. Since the phase transition process from γ-Na 2 C 6 O 6 to α-Na 2 C 6 O 6 during charging (de-sodiumization) needs to overcome a large activation energy, this phase transition usually exhibits a high degree of irreversibility, Seriously restricted Na 2Electrochemical performance of C 6 O 6 positive electrode. In order to solve this problem, the activation energy barrier of this phase transition can be reduced by reducing the grain size of Na 2 C 6 O 6 and selecting a suitable electrolyte solution, so that α-Na 2 C 6 O 6 The phase change with γ-Na 2 C 6 O 6 has a highly reversible characteristic, and realizes a sodium storage mechanism that reversibly stores 4 sodium atoms in each Na 2 C 6 O 6 unit cell, thereby achieving a high Reversible capacity and cycle stability. Electrochemical tests show that when DEGDME with strong solvation is selected as the electrolyte solution, the nano-sized Na 2 C 6 O 6 positive electrode can reach a reversible capacity of 484 mAh / g and an energy of 726 Wh / kg Density (based on Na 2 C 6 O 6 positive electrode), its energy efficiency is as high as 87%, and has a high capacity retention rate. The Na 2 C 6The specific energy of the O 6 positive electrode is as high as 96.6% of its theoretical value, and exceeds all the previously reported positive electrode materials for sodium ion batteries. This discovery sheds light on the construction of a sustainable high-performance large-scale energy storage system. The research result was titled " High-performance sodium–organic battery by realizing four-sodium storage in disodium rhodizonate " and was published on Nature Energy . The first author of this work was postdoctoral Minah Lee of the School of Chemical Engineering at Stanford University .

Literature link: High-performance sodium–organic battery by realizing four-sodium storage in disodium rhodizonate (Nat. Energy, 2017, DOI: 10.1038 / s41560-017-0014-y)

8.Nat. Commun .: Insulation tool-metalized polyethylene fabric with nano holes

Professor Cui Yi‘s team at Stanford University published an article entitled " Warming up human body by nanoporous metallized polyethylene textile" in Nature Communications , which pointed out the possibility of using metalized polyethylene to make clothing with superior thermal insulation in the future. The team successfully constructed a one-dimensional steady-state heat transfer model, and obtained the relationship between the infrared performance of clothing and the outside temperature under the condition of constant human skin temperature in a cold environment. The study found that the infrared emissivity of the outer surface of the fabric has an important effect on the insulation performance of the clothing, while the infrared emissivity of the inner surface of the fabric has almost no effect on the insulation performance. The team further designed a low-infrared emissivity (10.1%) metallized polyethylene fabric with nanopores. After wearing this kind of clothing, even if the external heating temperature is reduced by 7.1 ℃, the human comfort will not be affected influences. The results of this research are expected to greatly reduce the demand for heating of the living room, which will have a profound impact on the effective use of resources and sustainable development in the future.

Literature link: Warming up human body by nanoporous metallized polyethylene textile (Nature Communication, 8, Article number: 496 (2017) Doi: 10.1038 / s41467-017-00614-4)

9.Nat. Commun .: Activation reaction of inactive sulfide in lithium-sulfur battery

Professor Cui Yi of Stanford University reported on Nat. Commun. That a method of adding cheap sulfur and heating by stirring to activate this inactive sulfide can achieve the purpose of suppressing the loss of battery capacity. The capacity of a single battery can reach 0.9 Ah, and the volume energy density can reach 95 Wh / L (3M Li 2 S 8 ), which is about 4 times that of a full vanadium flow battery. And the volume energy density of Li 2 S 8 (5M) at high concentration can reach 135 Wh / L. This study for the first time increased the loading of the active material to 0.125 g / cm ³ (about 2 g S in a single battery), and achieved excellent performance.

Literature link: Reactivation of dead sulfide species in lithium polysulfide flow battery for grid scale energy storage (Nat. Commun., 2017, doi: 10.1038 / s41467-017-00537-0)

10.Science Advances: Overlithiated mesoporous AlF-3 frame is used to construct metal lithium battery negative electrode with high current density

From Professor Yi Cui of Stanford University team (corresponding author) in sub-famous Science Journal Science Advances on entitled " Ultrahigh-Density Current Anodes with Interconnected Li Metal Reservoir through overlithiation of Mesoporous AlF 3 Framework " article, first author Hansen Wang (王瀚森) . This paper reports a use of Al . 4 of Li of 9- -LiF body frame as a stable, three-dimensional metallic lithium by the mesoporous AlF- . 3 simple step through the process of embedding the lithium nano composite (of Li / of Al . 4 of Li of 9- - LiF, LAFN), to build a new metal lithium anode method. This LAFN is an ideal body frame with almost zero volume change during lithium stripping / deposition. Although the frame occupies space, the metal lithium in the LAFN composite still has a high specific capacity of 1571mAh g ^-1 and a volume capacity of 1447mAh cm ^-3 . At the same time, it promotes the diffusion of lithium ions, improves the interface between the lithium metal and the electrolyte, and effectively inhibits the growth of lithium dendrites. Due to these advantages, the metal lithium electrode can reach 20mA cm ^‑2Circulate at least 100 times at high current density, and improve the performance of the full battery at high rates and improve the Coulomb efficiency.

Literature link: Ultrahigh–current density anodes with interconnected Li metal reservoir through overlithiation of mesoporous AlF 3 framework (Science Advances: 10.1126 / sciadv.1701301)

11.JACS: Surface fluorination enhances the stability of negative materials for active batteries

Professor Cui Yi (corresponding author) of Stanford University proposed the use of fluoropolymer CYTOP as a solid and non-toxic source of fluorine, and developed a convenient surface fluorination process. Among common fluoropolymers, only CYTOP decomposes at a relatively low temperature and gradually releases pure fluorine gas, which reacts with Li metal or a pre-lithiated Si anode to form a uniform and dense LiF coating. The LiF coating layer has excellent chemical stability in a highly reducing environment, has extremely low solubility in the electrolyte, and has strong mechanical properties, which minimizes the corrosion reaction between the Li metal and the carbonate-type electrolyte, and suppresses branching.晶 形成。 Crystal formation. Therefore, LiF-protected Li metal anodes showed no dendrites and stable cycles in 300 cycles at current densities of 1 mA / cm ² and 5 mA / cm ² . Due to the crystalline and dense LiF coating, Li x Si NPs can be processed in NMP and have a high capacity of 2504 mAh / g. They show excellent stability in humid air (~ 40% RH) and have a capacity retention rate of 85.9% after 1 day. During the operation of the battery, due to the protection of the inert LiF coating, the decomposition of the electrolyte is effectively suppressed, so that the LiF-Li x Si NPs maintain a high CE during the long-term cycle The average CE is 99.92%). This achievement was published on J. Am. Chem. Soc. Under the title " Surface Fluorination of Reactive Battery Anode Materials for Enhanced Stability" . The first author of this article is Dr. Zhao Jie of Stanford University, and the co-first author is Liao Lei, a postdoctoral fellow of Stanford University .

Literature link : Surface Fluorination of Reactive Battery Anode Materials for Enhanced Stability (J. Am. Chem. Soc., 2017, DOI: 10.1021 / jacs.7b05251)

12. Nano Lett .: Reveal the nano-scale passivation and corrosion mechanism of active battery materials in a gas environment

The development of renewable energy generation and storage of advanced materials is very important for sustainable future development. New breakthroughs are determined by a deep understanding of materials. The use of X-rays and electron microscopes / spectroscopy for real-time detection of chemical and electrochemical reactions for researchers We have provided a way to study the mechanism of battery, catalysis and nanocrystal synthesis at the nano level. When the material has high chemical activity, there will be more challenges to its research. For example, lithium metal easily loses its gloss under air, which will affect the in-situ TEM observation of sensitive materials that depend on the environment. To study these active materials requires preparing pure phase samples that are not exposed to the environment, and the chemical and electrochemical reactions in the environment can be continuously observed. In this paper, the researchers confirmed the important role of this method by directly electrodepositing lithium metal in a high-vacuum TEM chamber and subsequently exposing to specific gases for in-situ observation.

Recently, Professor Cui Yi from Stanford University published an article entitled " Revealing Nanoscale Passivation and Corrosion Mechanisms of Reactive Battery Materials in Gas Environments. " In Nano Letter . The article explains the details of the lithium metal passivation / corrosion process and confirms how the mechanism guides the lithium metal battery engineering program.

Original link: Revealing Nanoscale Passivation and Corrosion Mechanisms of Reactive Battery Materials in Gas Environments . (Nano Lett., 2017, DOI: 10.1021 / acs.nanolett.7b02630)

13.AEM: Viscoelastic membrane helps wave-shaped stretchable lithium-ion battery

Professor Cui Yi ( corresponding author ) from Stanford University published an article entitled " Stretchable Lithium-Ion Batteries Enabled by Device-Scaled Wavy Structure and Elastic-Sticky Separator " in the famous journal Advanced Energy Materials . This article reports a simple method for constructing a fully wavy stretchable lithium ion battery (it is worth noting that the lithium ion battery is a macro wave structure). All components of the battery including the cathode, anode, separator, current collector and even the packaging material can be stretched at the same time. The final assembled wavy stretchable lithium ion battery exhibits high energy density and good cycle stability.

Literature link: Stretchable Lithium-Ion Batteries Enabled by Device-Scaled

Wavy Structure and Elastic-Sticky Separator (Adv. Energy.Mater: 10.1002 / aenm.201701076)

14.ACS Nano: Atomic layer deposition of stable LiAlF4 lithium ion conductive interface layer is used to stabilize the positive electrode cycle

Professor Cui Yi (corresponding author) from Stanford University in the United States and others published an article on ACS Nano , entitled " Atomic Layer Deposition of Stable LiAlF 4 Lithium Ion Conductive Interfacial Layer for Stable Cathode Cycling ". The researchers prepared by using atomic layer deposition technology A solid film of LiAlF 4 with high stability and satisfactory ionic conductivity has been developed . The performance of this material is better than that of LiF and AlF 3 commonly used . The predicted stable electrochemical window of LiAlF 4 is approximately 2.0 ± 0.9 to 5.7 ± 0.7 V vs Li ⁺ / Li. At the same time, the composite material of LiNi 0.8 Mn 0.1 Co 0.1 O 2 electrode with high Ni content and LiAlF 4 interface layer achieves excellent stability under a wide electrochemical window of 2.75−4.50 V vs Li ⁺ / Li.

Literature link: Atomic Layer Deposition of Stable LiAlF 4 Lithium Ion Conductive Interfacial Layer for Stable Cathode Cycling (ACS Nano, 2017, DOI: 10.1021 / acsnano.7b02561)

15. Nature Nanotechnology: Lithium metal anode replacement-lithium alloy / graphene anode!

The team of Professor Cui Yi (corresponding author) from Stanford University published the research results entitled "Air-stable and freestanding lithium alloy / graphene foil as an alternative to lithium metal anodes" in Nature Nanotechnology. The researchers first coated the prepared lithium alloy (Li x M) nanoparticles in graphene (<10 layers) materials with excellent hydrophobic properties and low gas permeability, and then applied the lithium alloy / graphene anode materials separately In a lithium battery using LiFePO 4 , V 2 O 5 , and S as a positive electrode material, and using lithium metal negative electrode and graphene negative electrode as reference experiments, the electrochemical performance of the battery was tested under the condition of high current density charge and discharge. The negative electrode materials were characterized by SEM, TEM, XPS, flexibility and strength, and hydrophobicity. The results show that the battery with lithium alloy / graphene as the negative electrode can still maintain 98% of the initial capacity after 400 charge and discharge cycles at high current density, mainly because: (1) Li x M alloy material can effectively deal with Changes in volume expansion caused by lithium intercalation-delithiation process; (2) The coated graphene material has better hydrophobic properties, lower gas permeability, and improves the stability of the negative electrode (prevents from air, water, Electrolyte reaction); (3) For lithium-sulfur batteries, the coated graphene material inhibits the reaction of the polysulfide compound with the negative electrode, reduces the loss of positive electrode sulfur active materials, and maintains the capacity of the battery.

Literature link: Air-stable and freestanding lithium alloy / graphene foil as an alternative to lithium metal anodes ( Nature Nanotechnology, 2017, doi: 10.1038 / nnano.2017.129 )

16.JACS: Resolve electrochemically tuned LiCoO2 active crystal plane through oxygen evolution reaction

The Cui Yi team at Stanford University studied the enhancement effect of electrochemical deintercalation to determine the difference in oxygen evolution reactivity of lithium cobaltate (LCO) materials at different locations. Theoretical calculations indicate that the precipitation of lithium on the surface of lithium cobaltate is due to the increase in the number of Co ⁴⁺ sites compared to Co ³⁺ sites. The change of oxygen evolution reaction activity can be attributed to the transfer of oxygen 2p electrons. In the nanosheet LCO test, the electrochemical deintercalation has a negligible improvement in the oxygen evolution reaction activity of the (0001) plane that accounts for the vast majority of the exposed crystal planes, but in the nanometer In the detection of particles, electrochemical de-embedding significantly improves the oxygen evolution reaction of the material. In addition, the team also used electrochemical etching methods to create more active sites on the electrochemically deintercalated lithium cobaltate (De-LCO), which improved the oxygen evolution reactivity of the material. Theory. The article introduced in this article was published in the Journal of the American Chemical Society (JACS) on April 18, 2017. The corresponding author is Professor Cui Yi from Stanford University.

Literature link : Identifying the active surfaces of electrochemically tuned LiCoO 2 for oxygen evolution reaction (J. Am. Chem. Soc., 2017, DOI: 10.1021 / jacs.7b02622)

17.PNAS: A three-dimensional stable lithium metal anode prepared by embedding nano-lithium metal in an ionic conductive solid matrix

Professor Cui Yi from the Department of Materials Science and Engineering at Stanford University and the Stanford Institute of Materials and Energy Sciences published an article entitled "Three-dimensional stable lithium metal anode with nanoscale lithium islands embedded in ionically conductive solid matrix" in the international journal PNAS Research Papers. The researchers used a simple chemical synthesis method to embed nano-scale lithium metal into a conductive solid matrix to prepare a three-dimensional stable lithium ion conductive nanocomposite electrode (LCNE), and experimentally proved that the structure of the electrode has a small volume change And greatly reduced side reactions, this method has also successfully solved the problem of dendrite enlargement, creating a new design idea for the design of lithium metal anodes.

Literature link: Three-dimensional stable lithium metal anode with nanoscale lithium islands embedded in ionically conductive solid matrix (PNAS, 2017, DOI: 10.1073 / pnas.1619489114).

18. Nature Energy: Orderly arranged ceramic nanowires significantly enhance the ion conductivity of the composite polymer electrolyte

In solid polymer electrolytes containing polymers and lithium salts, inorganic nanoparticles are often used as fillers to improve electrochemical performance, structural stability, and mechanical strength. However, such composite polymer electrolytes generally have low ionic conductivity. On April 4, 2017, Beijing time, the research group of Professor Cui Yi from Stanford University published an article entitled " Enhancing ionic conductivity in composite polymer electrolytes with well-aligned ceramic nanowires " on Nature Energy , reporting that the The composite polymer electrolyte of inorganic Li ⁺ conductive nanowires exhibited an ion conductivity of 6.05 × 10 ^-5 S cm ^-1 at 30 ° C , which is an order of magnitude higher than the previously randomly oriented polymer electrolyte. The enhanced conductivity of the nanowires is due to the fast ion conduction path, and there is no cross-junction on the surface of the ordered nanowires. In addition, the use of nanowires can also improve the long-term structural stability of the polymer electrolyte.

Literature link: Enhancing ionic conductivity in composite polymer electrolytes with well-aligned ceramic nanowires (Nature Energy, 2017, doi: 10.1038 / nenergy.2017.35)

19.JACS: "solid-liquid" hybrid mechanical properties of plasticine can significantly improve the stability of next-generation lithium metal batteries

Professor Stanford Cui Yi‘s research group used plasticine as a protective coating for metal lithium anodes. They found that the "solid-liquid" hybrid nature of plasticine makes it an excellent adaptive protective layer for metal lithium anodes: (1 ) During the normal charge and discharge process, the "liquid" nature of the plasticine allows it to flow slowly during the change of lithium metal. Therefore, no matter how the volume and shape of lithium metal change, the plasticine can perfectly cover the surface of lithium and play a protective role. At this time, the plasticine coating can reduce the direct contact between the highly active lithium and the electrolyte, thereby effectively reducing the occurrence of side reactions. (2) If the lithium metal produces "hot spots" of lithium deposition in certain places on the surface, causing the lithium dendrites to "stab", the shear force on the plasticine coated on it will become larger, thereby making its mechanical strength Increase, reflecting the "solid" nature. (3) The properties of "solid" and "liquid" of plasticine can be reversibly changed with the growth and elimination of lithium dendrites, thus ensuring the normal and stable operation of metal lithium anodes.

Literature link : Lithium Metal Anodes with an Adaptive “Solid-Liquid” Interfacial Protective Layer .

20. PNAS: Catalytic oxidation of polysulfides on the surface of metal sulfides in lithium-sulfur batteries

Materials Science and Engineering at Stanford University ‘s Professor Yi Cui , Materials Science and Engineering, Beijing University of Aeronautics and Astronautics of Zhang Qian, associate professor and Singapore Materials Research works of Zhi Wei She union in PNAS entitled the " Catalytic Oxidation of Li 2 S ON The surface of metal sulfides for Li−S batteries ”article reveals the catalytic oxidation mechanism of Li 2 S on the surface of metal sulfides in lithium-sulfur (Li-S) batteries , and does a series of metal sulfide In-depth research. By combining density functional theory (DFT) simulations and experimental tests, the researchers found that when the metal sulfide is used as the host material, the size of its catalytic oxidation / reduction ability is crucial for the transportation of lithium ions and the adsorption of polysulfides (LiPSs). important. The strong metal-sulfide inherent metal conductivity and the strong interaction between Li 2 S / Li 2 S x can reduce the energy barrier