易燃液体无损光谱检测技术综述

易燃液体在食品、化工、能源等领域均有广泛应用,并创造了巨大的经济价值.然而,该类液体易燃易爆,且在使用过程中可能会产生有毒蒸汽,因而它的无损检测对于促进工业生产和保障人民的人身财产安全具有深远意义.光谱检测技术具有快速、在线检测、无损、样品无需预处理、检测精度高等优点,在易燃液体检测中发挥了重要作用.本文综述了易燃液体...     

HL-2A装置上利用可见轫致辐射测量有效电荷数

在HL-2A装置中,利用多道可见轫致辐射系统测量的弦积分信号计算有效电荷数。对比分析不同放电位形,得出不同的有效电荷数径向分布并且在偏滤器位形时有效电荷数比孔栏位形时小约50%。此外,还统计分析了2010年春季实验的有效放电,显示出偏滤器对杂质的抑制作用。分析了不同的等离子体加热方式,电子回旋加热期间有效电荷数明显升高,而两种加热方式同时进行时中性束注入加热可以抑制有效电荷数的增加。     

VOC enhancement in polymer solar cells with isobenzofulvene–C60 adducts

We report the use of isobenzofulvene–C₆₀ adducts in bulk heterojunction organic solar cells, synthesized via the [4 + 2] cycloaddition of C₆₀ with an in situ generated isobenzofulvene intermediate. The LUMO energy levels of these adducts are 20–180 meV higher than that of PCBM ([6,6]-phenyl-C₆₁-butyric acid methyl ester). This large increase of the LUMO level is attributed to cofacial π-orbital interactions between the fullerene surface and the isobenzofulvene π–system (aromatic ring and double bond). Raised LUMO levels of fullerenes, together with their desirably slow recombination dynamics, led to higher open-circuit voltages (V_OC) in bulk heterojunction polymer solar cells (up to 0.75 V for bisadducts) relative to cells tested in parallel using the well-known PCBM as the fullerene acceptor. In addition to enhanced V_OC, the short-circuit current densities (J_SC) were improved in the devices containing the epoxide analogs of the isobenzofulvene–C₆₀. Notably the epoxide derivative of the monoadduct (IBF–Ep) exhibited ∼20% enhancement of power conversion efficiency (PCE) compared to reference P3HT:PCBM solar cells. A combination of optical and electronic methods was used to investigate the origin of the PCE enhancement observed with these new fullerene acceptors with particular attention to the increased V_OCs.     

Tuning a Solvation Structure of Lithium Ions Coordinated with Nitrate Anions through Ionic Liquid-Based Solvent for Highly Stable Lithium Metal Batteries

Rational design of promising electrolyte is considered as an effective strategy to improve the cycling stability of lithium metal batteries (LMBs). Here, an elaborately designed ionic liquid-based electrolyte is proposed that is composed of lithium bis(trifluoromethanesulfonyl)imide as the lithium salt, 1-ethyl-3-methylimidazolium nitrate ionic liquid ([EMIm][NO₃] IL) and fluoroethylene carbonate (FEC) as the functional solvents, and 1,2-dimethoxyethane (DME) as the diluent solvent. Using [EMIm][NO₃] IL as the solvent component facilitates a special Li⁺-coordinated NO₃⁻ solvation structure, which enables the continues electrochemical reduction of solvated NO₃⁻ and the formation of remarkably stable and conductive solid electrolyte interface. With FEC as another functional solvent and DME as the diluent solvent, the formulated electrolyte delivers high oxidative stability and ionic conductivity, and endows improved electrochemical reaction kinetics. Therefore, the formulated electrolyte demonstrates exceedingly reversible and stable Li stripping/plating behavior with high average Coulombic efficiency (98.8%) and ultralong cycling stability (3500 h). Notably, the high-voltage Li|LiNi_0.8Co_0.1Mn_0.1O₂ full cell with IL-based electrolyte exhibits enhanced cyclability with a capacity retention of 65% after 200 cycles under harsh conditions of low negative/positive ratio (3.1) and lean electrolyte (2.5 µL mg⁻¹). This study creates the first NO₃⁻-based ionic liquid electrolyte and evokes the avenue for practical high-voltage LMBs.     

An Intrinsically Nonflammable Electrolyte for Prominent-Safety Lithium Metal Batteries with High Energy Density and Cycling Stability

Nex-generation high-energy-density storage battery, assembled with lithium (Li)-metal anode and nickel-rich cathode, puts forward urgent demand for advanced electrolytes that simultaneously possess high security, wide electrochemical window, and good compatibility with electrode materials. Herein an intrinsically nonflammable electrolyte is designed by using 1 M lithium difluoro(oxalato)borate (LiDFOB) in triethyl phosphate (TEP) and N-methyl-N-propyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide [Pyr₁₃][TFSI] ionic liquid (IL) solvents. The introduction of IL can bring plentiful organic cations and anions, which provides a cation shielding effect and regulates the Li⁺ solvation structure with plentiful Li⁺-DFOB⁻ and Li⁺-TFSI⁻ complexes. The unique Li⁺ solvation structure can induce stable anion-derived electrolyte/electrode interphases, which effectively inhibit Li dendrite growth and suppress side reactions between TEP and electrodes. Therefore, the LiNi_0.9Co_0.05Mn_0.05O₂ (NCM90)/Li coin cell with this electrolyte can deliver stable cycling even under 4.5 V and 60 °C. Moreover, a Li-metal battery with thick NCM90 cathode (≈ 15 mg cm⁻²) and thin Li-metal anode (≈ 50 µm) (N/P ≈ 3), also reveals stable cycling performance under 4.4 V. And a 2.2 Ah NCM90/Li pouch cell can simultaneously possess prominent safety with stably passing the nail penetration test, and high gravimetric energy density of 470 Wh kg⁻¹ at 4.4 V.     

Toward a Magnesium‐Iodine Battery

The quest for new electrolyte and cathode materials is a crucial point for beyond‐lithium‐ion energy storage systems. Following this, an electrolyte for secondary magnesium batteries based on a new iodoaluminate ionic liquid and δ‐MgI₂ is reported. Promising electrochemical performance in terms of Mg plating‐stripping, coulombic efficiency, and conductivity, demonstrates the potential of this iodine‐based system for future Mg secondary batteries.     

Ionic Liquid Analogs of AlCl3 with Urea Derivatives as Electrolytes for Aluminum Batteries

The ionic liquid analog, formed through the mixture of urea and AlCl₃, has previously shown to serve as a low‐cost electrolyte for an aluminum‐graphite battery, while maintaining good performance and achieving high Coulombic efficiency. Undesirable are the relatively high viscosity and low conductivity of this electrolyte, when compared to chloroaluminate ionic liquids with organic cations. In this work, the fundamental changes to the electrolyte resulting from using derivatives of urea (N‐methyl urea and N‐ethyl urea), again mixed with AlCl₃, are examined. These electrolytes are shown to have significantly lower viscosities (η = 45, 67, and 133 cP when using N‐ethyl urea, N‐methyl urea, and urea, respectively, at 25 °C). The associated batteries exhibit higher intrinsic discharge voltages (2.04 and 2.08 V for N‐methyl urea and N‐ethyl urea electrolytes, respectively, vs 1.95 V for urea system@100 mA g^?1 specific current for ≈5 mg cm^?2 loading), due to changes in concentrations of ionic species. Aluminum deposition is directly observed to primarily occur through reduction of Al₂Cl₇^? when AlCl₃ is present in excess, in contrast to previously suggested cationic Al‐containing species, via operando Raman spectroscopy performed during cyclic voltammetry.     

Metal-Organic Framework Thin Films Grown on Functionalized Graphene as Solid-State Ion-Gated FETs

The unique properties of 2D-materials like graphene are exploited in various electronic devices. In sensor applications, graphene shows a very high sensitivity, but only a low specificity. This shortcoming can be mastered by using heterostructures, where graphene is combined with materials exhibiting high analyte selectivities. Herein, this study demonstrates the precise deposition of nanoporous metal-organic frameworks (MOFs) on graphene, yielding bilayers with excellent specificity while the sensitivity remains large. The key for the successful layer-by-layer deposition of the MOF films (SURMOFs) is the use of planar polyaromatic anchors. Then, the MOF pores are loaded with ionic liquid (IL). For functioning sensor devices, the IL@MOF films are grown on graphene field-effect transistors (GFETs). Adding a top-gate electrode yields an ion-gated GFET. Analysis of the transistor characteristics reveals a clear Dirac point at low gate voltages, good on-off ratios, and decent charge mobilities and densities in the graphene channel. The GFET-sensor reveals a strong and selective response. Compared to other ion-gated-FET devices, the IL@MOF material is relatively hard, allowing the manufacturing of ultrathin devices. The new MOF-anchoring strategy offers a novel approach generally applicable for the functionalization of 2D-materials, where MOF/2D-material hetero-bilayers carry a huge potential for a wide variety of applications.     

Super-Stretchable,Anti-Freezing,Anti-Drying Organogel Ionic Conductor for Multi-Mode Flexible Electronics

Due to their intrinsic flexibility, tunable conductivity, multiple stimulus-response, and self-healing ability, ionic conductive hydrogels have drawn significant attention in flexible/wearable electronics. However, challenges remain because traditional hydrogels inevitably faced the problems of losing flexibility and conductivity because of the inner water loss when exposed to the ambient environment. Besides, the water inside the hydrogel will freeze at the water icing temperatures, making the device hard and fragile. As a promising alternative, organogels have attracted wide attention because they can, to some extent, overcome the above drawbacks. Herein, a kind of organogel ionic conductor (MOIC) by a self-polymerization reaction is involved, which is super stretchable, anti-drying, and anti-freezing. Meanwhile, it can still maintain high mechanical stability after alternately loading/unloading at the strain of 600% for 600 s (1800 cycles). Using this MOIC, high-performance triboelectric nanogenerator (TENG) is constructed (MOIC-TENG) to harvest small mechanical energy even the MOIC electrode underwent an extremely low temperature. In addition, multifunctional flexible/wearable sensors (strain sensor, piezoresistive sensor, and tactile sensor) are realized to monitor human motions in real time, and recognize different materials by triboelectric effect. This study demonstrates a promising candidate material for flexible/wearable electronics such as electronic skin, flexible sensors, and human-machine interfaces.