Decomposition schemes of copper(I) N,N'-diisopropylacetamidinate during chemical vapor deposition of copper

Copper(I) N,N'-diisopropylacetamidinate [Cu(amd)]2 (amd = CH(CH3)2NC(CH3)NCH(CH3)2), an oxygen and halogen-free compound, was previously tested as precursor for pure copper CVD and ALD films. The present work deals with the investigation of the composition and of the reactivity of the gas phase during the CVD process. The work was performed by mass spectrometry as a function of temperature in two different, though complementary environments: (A) in a miniature, low pressure hot wall CVD reactor, (B) in a cold wall reactor operating at subatmospheric pressure. (A) revealed that the onset of thermal decomposition is 140 degrees C and 130 degrees C in vacuum and in the presence of hydrogen, respectively; maximal decomposition degree is reached at temperature higher than 200 degrees C. The protonated ligand H(amd) is the main gaseous decomposition by-product; propene CH2=CHCH3, acetonitryle CH3C[triple bond]N and iminopropane CH3C(CH3)=NH are also observed in vacuum. Heterogeneous decomposition mechanism both in vacuum and hydrogen presence is discussed.     

Aliphatic Polycarbonate‐Based Solid‐State Polymer Electrolytes for Advanced Lithium Batteries: Advances and Perspective

Conventional liquid electrolytes based lithium‐ion batteries (LIBs) might suffer from serious safety hazards. Solid‐state polymer electrolytes (SPEs) are very promising candidate with high security for advanced LIBs. However, the quintessential frailties of pristine polyethylene oxide/lithium salts SPEs are poor ionic conductivity (≈10⁻⁸ S cm⁻¹) at 25 °C and narrow electrochemical window (<4 V). Many innovative researches are carried out to enhance their lithium‐ion conductivity (10⁻⁴ S cm⁻¹ at 25 °C), which is still far from meeting the needs of high‐performance power LIBs at ambient temperature. Therefore, it is a pressing urgency of exploring novel polymer host materials for advanced SPEs aimed to develop high‐performance solid lithium batteries. Aliphatic polycarbonate, an emerging and promising solid polymer electrolyte, has attracted much attention of academia and industry. The amorphous structure, flexible chain segments, and high dielectric constant endow this class of polymer electrolyte excellent comprehensive performance especially in ionic conductivity, electrochemical stability, and thermally dimensional stability. To date, many types of aliphatic polycarbonate solid polymer electrolyte are discovered. Herein, the latest developments on aliphatic polycarbonate SPEs for solid‐state lithium batteries are summarized. Finally, main challenges and perspective of aliphatic polycarbonate solid polymer electrolytes are illustrated at the end of this review.     

2D Frameworks of C2N and C3N as New Anode Materials for Lithium‐Ion Batteries

Novel layered 2D frameworks (C₃N and C₂N‐450) with well‐defined crystal structures are explored for use as anode materials in lithium‐ion batteries (LIBs) for the first time. As anode materials for LIBs, C₃N and C₂N‐450 exhibit unusual electrochemical characteristics. For example, C₂N‐450 (and C₃N) display high reversible capacities of 933.2 (383.3) and 40.1 (179.5) mAh g^?1 at 0.1 and 10 C, respectively. Furthermore, C₃N shows a low hypothetical voltage (≈0.15 V), efficient operating voltage window with ≈85% of full discharge capacity secured at >0.45 V, and excellent cycling stability for more than 500 cycles. The excellent electrochemical performance (especially of C₃N) can be attributed to their inherent 2D polyaniline frameworks, which provide large net positive charge densities, excellent structural stability, and enhanced electronic/ionic conductivity. Stable solid state interface films also form on the surfaces of the 2D materials during the charge/discharge process. These 2D materials with promising electrochemical performance should provide insights to guide the design and development of their analogues for future energy applications.     

Characteristics of a Graphene Nanoplatelet Anode in Advanced Lithium‐Ion Batteries Using Ionic Liquid Added by a Carbonate Electrolyte

A Cu‐supported, graphene nanoplatelet (GNP) electrodes are reported a as high performance anode in lithium ion battery. The electrode precursor is an easy‐to‐handle aqueous ink cast on cupper foil and following dried in air. The scanning electron microscopy evidences homogeneous, micrometric flakes‐like morphology. Electrochemical tests in conventional electrolyte reveal a capacity of about 450 mAh g⁻¹ over 300 cycles, delivered at a current rate as high as 740 mA g⁻¹. The graphene‐based electrode is characterized using a N‐butyl‐N‐methyl‐pyrrolidiniumbis (trifluoromethanesulfonyl) imide, lithium‐bis(trifluoromethanesulfonyl)imide (Py_1,4TFSI–LiTFSI) ionic liquid‐based solution added by ethylene carbonate (EC): dimethyl carbonate (DMC). The Li‐electrolyte interface is investigated by galvanostatic and potentiostatic techniques as well as by electrochemical impedance spectroscopy, in order to allow the use of the graphene‐nanoplatelets as anode in advanced lithium‐ion battery. Indeed, the electrode is coupled with a LiFePO₄ cathode in a battery having a relevant safety content, due to the ionic liquid‐based electrolyte that is characterized by an ionic conductivity of the order of 10⁻² S cm⁻¹, a transference number of 0.38 and a high electrochemical stability. The lithium ion battery delivers a capacity of the order of 150 mAh g⁻¹ with an efficiency approaching 100%, thus suggesting the suitability of GNPs anode for application in advanced configuration energy storage systems.     

Binding of aromatic isocyanides on gold nanoparticle surfaces investigated by surface-enhanced Raman scattering

The adsorption structure and binding of phenyl isocyanide (PNC), 2,6-dimethyl phenyl isocyanide (DMPNC), and benzyl isocyanide (BZI) on gold nanoparticle surfaces have been studied by means of surface-enhanced Raman scattering (SERS). PNC, DMPNC, and BZI have been found to adsorb on gold assuming a standing geometry with respect to the surfaces. The presence of the nu(CH) band in the SERS spectra denotes a vertical orientation of the phenyl ring of PNC, DMPNC, and BZI on Au. The lack of a substantial red shift and significant band broadening of the ring breathing modes implied that a direct ring pi orbital interaction with metal substrates should be quite low. For PNC, the band ascribed to the C-NC stretching vibration was found to almost disappear after adsorption on Au. On the other hand, the C-NC band remained quite strong for DMPNC after adsorption. This result suggests a rather bent angle of C-N[triple bond]C: for the nitrogen atom of the NC binding group on the surfaces, whereas a linear angle of C-N[triple bond]C: should be more favorable on gold surfaces due to an intramolecular steric hindrance of its two methyl groups. SERS of BZI on gold nanoparticles also supports a bent angle of :C[triple bond]N-CH2 for its nitrogen atom, suggesting a preference of sp3 (or sp2) hybridization for the nitrogen atom.     

Yolk–Shell MnO@ZnMn2O4/N–C Nanorods Derived from α‐MnO2/ZIF‐8 as Anode Materials for Lithium Ion Batteries

Manganese oxides (MnO_x) are promising anode materials for lithium ion batteries, but they generally exhibit mediocre performances due to intrinsic low ionic conductivity, high polarization, and poor stability. Herein, yolk–shell nanorods comprising of nitrogen‐doped carbon (N–C) coating on manganese monoxide (MnO) coupled with zinc manganate (ZnMn₂O₄) nanoparticles are manufactured via one‐step carbonization of α‐MnO₂/ZIF‐8 precursors. When evaluated as anodes for lithium ion batteries, MnO@ZnMn₂O₄/N–C exhibits an reversible capacity of 803 mAh g^?1 at 50 mA g^?1 after 100 cycles, excellent cyclability with a capacity of 595 mAh g^?1 at 1000 mAg^?1 after 200 cycles, as well as better rate capability compared with those non‐N–C shelled manganese oxides (MnO_x). The outstanding electrochemical performance is attributed to the unique yolk–shell nanorod structure, the coating effect of N–C and nanoscale size.     

锂离子电池玻璃态电解质导电机理的研究进展

锂离子电池玻璃态电解质同晶体型电解质相比较具有导电性各向同性、锂离子电导率高等诸多优点, 开发在室温下具有较高的离子电导率及良好的化学、电化学稳定性的玻璃态电解质材料已经成为锂离子电池领域的重要研究方向之一。本文介绍了各种玻璃态电解质体系的导电特性及导电机理, 并重点分析与讨论混合网络形成体效应在一些典型玻璃态电解质体系中的微观作用机理。本文还总结了混合网络形成体效应在玻璃态电解质中发生的前提条件, 并指出深入研究玻璃态电解质的导电机理对开发出具有优异电化学性能的无机非晶固态电解质体系具有重要的指导意义。     

高离子传导纳米多孔β-Li3PS4固态电解质的湿化学法制备

利用湿化学法,并采取逐步加热脱除沉淀中四氢呋喃分子的方式,制备具有高离子电导率和低活化能的纳米多孔β-Li 3PS 4固态电解质。利用同步热分析、X射线衍射、扫描电镜、拉曼光谱、氮气吸脱附和交流阻抗测试等手段研究不同处理阶段产物的形貌、结构和物相组成,并测试分析β-Li 3PS 4固态电解质的电化学性能。结果表明:采用该方法制备的纳米多孔β-Li 3PS 4固态电解质比表面积为 28.3m 2·g -1 ,平均孔径约23nm,电化学测试表明该电解质在20℃下的离子电导率为1.84×10 -4 S·cm -1 ,活化能为0.343eV,电子电导率为1.3×10 -8 S·cm -1 ,具有优异的电化学稳定性,与金属锂负极也具有良好的兼容性。     

A lithium superionic conductor

Batteries are a key technology in modern society. They are used to power electric and hybrid electric vehicles and to store wind and solar energy in smart grids. Electrochemical devices with high energy and power densities can currently be powered only by batteries with organic liquid electrolytes. However, such batteries require relatively stringent safety precautions, making large-scale systems very complicated and expensive. The application of solid electrolytes is currently limited because they attain practically useful conductivities (10(-2) S cm(-1)) only at 50-80 °C, which is one order of magnitude lower than those of organic liquid electrolytes. Here, we report a lithium superionic conductor, Li(10)GeP(2)S(12) that has a new three-dimensional framework structure. It exhibits an extremely high lithium ionic conductivity of 12 mS cm(-1) at room temperature. This represents the highest conductivity achieved in a solid electrolyte, exceeding even those of liquid organic electrolytes. This new solid-state battery electrolyte has many advantages in terms of device fabrication (facile shaping, patterning and integration), stability (non-volatile), safety (non-explosive) and excellent electrochemical properties (high conductivity and wide potential window).     

锂磷氧氮电解质在无机薄膜锂电池中的应用

锂磷氧氮(LiPON,lithium phosphorous oxynitride)薄膜具有较高的离子电导率,极低的电子电导率,很宽的电化学稳定窗口等优点而成为全固态无机薄膜锂电池首选的电解质材料.简要介绍了LiPON薄膜的特性与制备方法,综述了国内外LiPON薄膜为电解质的薄膜锂电池的研究情况,并简要评述了目前薄膜锂电池制备中遇到的困难和今后的研究方向.     

Maximizing ionic transport of Li1+xAlxTi2-xP3O12 electrolytes for all-solid-state lithium-ion storage: A theoretical study

The concept of all-solid-state batteries provides an efficient solution towards highly safe and long-life energy storage,while the electrolyte-related challenges impede their practical application.Li1+xAlxTi2-xP3O12 (0 ≤ x ≤ 1) with superior Li ionic conductivity holds the promise as an ideal solidstate electrolyte.The intrinsic mechanism to reach the most optimum ionic conductivity in Al-doped Li1+xAlxTi2-xP3O12,however,is unclear to date.Herein,this work intends to provide an atomic scale study on the Li-ion transport in Li1+xAlxTi2-xP3O12 electrolyte to rationalize how Al-dopant initiates interstitial Li activity and facilitate their easy mobility combining Density Functional Theory (DFT) and ab initio Molecular dynamics (AIMD) simulations.It is discovered that the interstitial Li ions introduced by Al dopants can effectively activate the neighboring occupied intrinsic Li-ions to induce a long-range mobility in the lattice and the maximum Li ionic conductivity is achieved at 0.50 Al doping concentration.The Li-ion migration paths in Li1+xAlxTi2-xP3O12 have investigated as the degree of distortion of[PO4]tetrahedra and[TiO6]octahedra resulted by different Al doping concentrations.The asymmetry of the surrounding distorted[PO4]and[TiO6]polyhedrons play a critical role in reducing the migration barrier of Li ions in Li1+xAlxTi2-xP3O12.The flexible[TiO6]polyhedrons with a capacity to accommodate the structural distortion govern the Li ionic conductivity in Li1+xAlxTi2-xP3O12.This work rationalizes the mechanism for the most optimum Li ionic conductivity in Al-doped LiTi2P3O12 electrolyte and,more importantly,paves a road for exploring novel all-solid-state lithium battery electrolytes.     

Graphene‐Analogues Boron Nitride Nanosheets Confining Ionic Liquids: A High‐Performance Quasi‐Liquid Solid Electrolyte

Solid electrolytes are one of the most promising electrolyte systems for safe lithium batteries, but the low ionic conductivity of these electrolytes seriously hinders the development of efficient lithium batteries. Here, a novel class of graphene‐analogues boron nitride (g‐BN) nanosheets confining an ultrahigh concentration of ionic liquids (ILs) in an interlayer and out‐of‐layer chamber to give rise to a quasi‐liquid solid electrolyte (QLSE) is reported. The electron‐insulated g‐BN nanosheet host with a large specific surface area can confine ILs as much as 10 times of the host's weight to afford high ionic conductivity (3.85 × 10^?3 S cm^?1 at 25 °C, even 2.32 × 10^?4 S cm^?1 at ?20 °C), which is close to that of the corresponding bulk IL electrolytes. The high ionic conductivity of QLSE is attributed to the enormous absorption for ILs and the confining effect of g‐BN to form the ordered lithium ion transport channels in an interlayer and out‐of‐layer of g‐BN. Furthermore, the electrolyte displays outstanding electrochemical properties and battery performance. In principle, this work enables a wider tunability, further opening up a new field for the fabrication of the next‐generation QLSE based on layered nanomaterials in energy conversion devices.     

Novel PEO-based composite solid polymer electrolytes incorporated with active inorganic–organic hybrid polyphosphazene microspheres

Inorganic–organic hybrid poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) (PZS) microspheres with active hydroxyl groups were incorporated in poly(ethylene oxide) (PEO), using LiClO₄ as a dopant salt, to form a novel composite polymer electrolyte (CPE). The polymer chain flexibility and crystallinity properties are studied by DSC. The effects of active PZS microspheres on the electrochemical properties of the PEO-based electrolytes, such as ionic conductivity, lithium ion transference number, and electrochemical stability window are studied by electrochemical impedance spectroscopy and steady-state current method. Maximum ionic conductivity values of 3.36 × 10⁻⁵ S cm⁻¹ at ambient temperature and 1.35 × 10⁻³ S cm⁻¹ at 80 °C with 10 wt.% content of active PZS microspheres were obtained and the lithium ion transference number was 0.34. The experiment results showed that the inorganic–organic hybrid polyphosphazene microspheres with active hydroxyl groups can enhance the ionic conductivity and increase the lithium ion transference number of PEO-based electrolytes more effectively comparing with traditional ceramic fillers such as SiO₂.     

高性能锂离子电池正极Calix[6]quinone（英文）

有机醌类化合物因其具有高的理论容量值而引起了人们的广泛关注.本文合成了一种新型的环状大分子Calix[6]quinone(C6Q),它由6个对苯醌单元组成,可提供12个电化学位点,是一种极具发展前景的锂离子正极材料.C6Q在0.1 C的电流密度下展示了高达423 mA h g^-1的初始放电比容量(理论放电比容量为447 mA h g^-1).经过100圈充放电循环之后,它的容量保持在216 mA h g^-1;经过300次循环之后,仍然拥有195 mA h g^-1的高容量.C6Q具有高容量和宽的电化学窗口,因此可以提供高达1201 W h kg^-1的能量密度.此外,使用有序介孔碳CMK-3固载C6Q的方法可以进一步提高C6Q的电化学性能.     

Fluorophilic ionophores for potentiometric pH determinations with fluorous membranes of exceptional selectivity

Ionophore-doped sensor membranes exhibit greater selectivities and wider measuring ranges when they are prepared with noncoordinating matrixes. Since fluorous phases are the least polar and least polarizable liquid phases known, a fluorous phase was used for this work as the membrane matrix for a series of ionophore-based sensors to explore the ultimate limit of selectivity. Fluorous pH electrode membranes, each comprised of perfluoroperhydrophenanthrene, sodium tetrakis[3,5-bis(perfluorohexyl)phenyl]borate, and one of four fluorophilic H(+)-selective ionophores were prepared. All the ionophores are highly fluorinated trialkylamines containing three electron withdrawing perfluoroalkyl groups shielded from the central nitrogen by alkyl spacers of varying lengths: [CF(3)(CF(2))(7)(CH(2))(3)](2)[CF(3)(CF(2))(6)CH(2)]N, [CF(3)(CF(2))(7)(CH(2))(3)](2)(CF(3)CH(2))N, [CF(3)(CF(2))(7)(CH(2))(3)](3)N, and [CF(3)(CF(2))(7)(CH(2))(5)](3)N. Their pKa values in the fluorous matrix are as high as 15.4 +/- 0.3, and the corresponding electrodes exhibit logarithmic selectivity coefficients for H(+) over K(+) as low as <-12.8. The pKa and selectivity follow the trends expected from the degree of shielding and the length of the perfluoroalkyl chains of the ionophores. These electrodes are the first fluorous ionophore-based sensors described in the literature. The selectivities of the sensor containing [CF(3)(CF(2))(7)(CH(2))(5)](3)N are not only greater than those of analogous sensors with nonfluorous membranes but were of the same magnitude as the best ionophore-based pH sensors ever reported.     

固态锂电池用MOF/聚氧化乙烯复合聚合物电解质

固态聚合物电解质具有柔韧性好和易于加工的优势,可制备各种形状的固态锂电池,杜绝漏液问题.但固态聚合物电解质存在离子电导率低以及对锂金属负极不稳定等问题.本研究以纳米金属-有机框架材料UiO-66为聚合物电解质的填料,用于改善电解质的性能.UiO-66与聚氧化乙烯(poly(ethylene oxide),PEO)链上醚...     

Effective Suppression of Lithium Dendrite Growth Using a Flexible Single‐Ion Conducting Polymer Electrolyte

A novel single‐ion conducting polymer electrolyte (SIPE) membrane with high lithium‐ion transference number, good mechanical strength, and excellent ionic conductivity is designed and synthesized by facile coupling of lithium bis(allylmalonato) borate (LiBAMB), pentaerythritol tetrakis (2‐mercaptoacetate) (PETMP) and 3,6‐dioxa‐1,8‐octanedithiol (DODT) in an electrospun poly(vinylidienefluoride) (PVDF) supporting membrane via a one‐step photoinitiated in situ thiol–ene click reaction. The structure‐optimized LiBAMB‐PETMP‐DODT (LPD)@PVDF SIPE shows an outstanding ionic conductivity of 1.32 × 10^?3 S cm^?1 at 25 °C, together with a high lithium‐ion transference number of 0.92 and wide electrochemical window up to 6.0 V. The SIPE exhibits high tensile strength of 7.2 MPa and elongation at break of 269%. Due to these superior performances, the SIPE can suppress lithium dendrite growth, which is confirmed by galvanostatic Li plating/stripping cycling test and analysis of morphology of Li metal electrode surface after cycling test. Li|LPD@PVDF|Li symmetric cell maintains an extremely stable and low overpotential without short circuiting over the 1050 h cycle. The Li|LPD@PVDF|LiFePO₄ cell shows excellent rate capacity and outstanding cycle performance compared to cells based on a conventional liquid electrolyte (LE) with Celgard separator. The facile approach of the SIPE provides an effective and promising electrolyte for safe, long‐life, and high‐rate lithium metal batteries.     

Electronic coupling in dimetallic complexes with pi-conjugated bridge

Compound 2, [(eta5-C5Me5) Fe(dppe)]2(mu-C[triple bond]C-CH==CH-C[triple bond]C), was prepared by the reaction of compound 1, [eta5-C5Me5) Fe(dppe)]2+ (mu2-C==CH-CH=CH-HC=C).(PF6)2-, with KOBu(t). Compound 2 showed two quasi-reversible one-electron oxidations at -0.674 and -0.253 V, respectively. The comproportionation constant, Kc, was calculated from these measurements. The mixed-valence(MV) radical cation 2+ showed an absorption peak at 1586 nm, which was assigned to the MV pi-pi band of the delocalized complex (Robin-Day Mixed-valence Class III) and the effective coupling parameter, Hab, is consistent with the presence of electronic delocalization.     

Catalytic reduction of dinitrogen to ammonia at well-defined single metal sites

Dinitrogen (N2) is reduced to ammonia at room temperature and 1atm with molybdenum catalysts that contain tetradentate [HIPTN3N]3- triamidoamine ligands {[HIPTN3N]3-=[{3,5-(2,4,6-i-Pr3C6H2)2C6H3NCH2CH2}3N]3-, an example being [HIPTN3N]Mo(N2)} in heptane. Slow addition of the proton source ({2,6-lutidinium}{BAr'4}; Ar'=3,5-(CF3)2C6H3) and reductant (decamethyl chromocene) assure a high yield of ammonia (63-65% in four turnovers) versus dihydrogen formation. Numerous X-ray studies, along with isolation and characterization of seven intermediates in the proposed catalytic reaction (under noncatalytic conditions), suggest that N2 is being reduced at a sterically protected, single Mo centre that cycles between states Mo(III), Mo(IV), Mo(V) and Mo(VI).     

A Lithium–Air Battery Stably Working at High Temperature with High Rate Performance

Driven by the increasing requirements for energy supply in both modern life and the automobile industry, the lithium–air battery serves as a promising candidate due to its high energy density. However, organic solvents in electrolytes are likely to rapidly vaporize and form flammable gases under increasing temperatures. In this case, serious safety problems may occur and cause great harm to people. Therefore, a kind of lithium–air that can work stably under high temperature is desirable. Herein, through the use of an ionic liquid and aligned carbon nanotubes, and a fiber shaped design, a new type of lithium–air battery that can effectively work at high temperatures up to 140 °C is developed. Ionic liquids can offer wide electrochemical windows and low vapor pressures, as well as provide high thermal stability for lithium–air batteries. The aligned carbon nanotubes have good electric and heat conductivity. Meanwhile, the fiber format can offer both flexibility and weavability, and realize rapid heat conduction and uniform heat distribution of the battery. In addition, the high temperature has also largely improved the specific powers by increasing the ionic conductivity and catalytic activity of the cathode. Consequently, the lithium–air battery can work stably at 140 °C with a high specific current of 10 A g^‐1 for 380 cycles, indicating high stability and good rate performance at high temperatures. This work may provide an effective paradigm for the development of high‐performance energy storage devices.