TFTTP作为阴极缓冲层提高有机薄膜太阳能电池的内建电场和载流子收集效率

采用一种新型的电子传输材料TFTTP作为阴极缓冲层提高基于SubPc/C₆₀异质结的有机薄膜太阳能电池的性能. 通过在有机活性层和金属电极之间加入TFTTP界面层,器件的能量转换效率提高了约30%. 系统研究了器件的二极管特性、光电流特性以及内部的光场分布情况,结果表明,TFTTP阴极缓冲层的引入可以有效地提高器件的内建电场,进而增加电荷转移激子的分离效率. 通过使用TFTTP作为阴极缓冲层,在C₆₀/金属界面形成良好的欧姆接触,降低了界面接触电阻,有利于自由载流子的收集.     

Reaction mechanisms of the copper-manganese spinel cathode in a solid oxide fuel cell

Cu_1.25Mn_1.75O₄ spinel (CMO) was studied as a potential solid oxide fuel cell (SOFC) cathode material at intermediate temperatures. The reaction mechanism of a composite cathode consisting of Cu_1.25Mn_1.75O₄ and yttria-stabilized zirconia (YSZ) was investigated by impedance spectroscopy. The influence of the CMO/YSZ ratio, time exposed to current passage and temperature on the impedance spectra was examined. Activation energy of the corresponding processes was calculated to be near 1 eV and between 1.32 and 1.96 eV for the high and low frequency arcs in the impedance spectra. Comparison between CMO-YSZ and Sr-doped LaMnO₃ (LSM)-YSZ composite cathodes showed they had similar reaction mechanisms. The transport or transfer of oxygen intermediates or oxide ions between the catalyst and electrolyte was suggested to be the rate determining steps between 700 and 800 °C, whereas dissociative adsorption, mass transfer and surface diffusion were rate controlling between 600 and 700 °C.     

Preparation of LiNi0.5Mn0.5O2 cathode materials by urea hydrolysis coprecipitation

Layered LiNi_0.5Mn_0.5O₂ has been successfully synthesized via urea hydrolysis coprecipitation method. Well-crystallized LiNi_0.5Mn_0.5O₂ was obtained after calcinations of coprecipitation precursors and lithium salts at 450 °C for 3 h and following 900 °C for 10 h in air. Both the precursors and LiNi_0.5Mn_0.5O₂ powders show an agglomerated secondary structure with crystalline particles inside. The quasi-spherical morphology of the precursors was maintained during the calcinations. The first charge and discharge capacities of as-prepared LiNi_0.5Mn_0.5O₂ were 200 and 165mAh/g respectively. The discharge capacity of about 160mAh/g was retained after 10cycles for as-prepared samples.     

Conductivity and sintering property of LaNi1 − xFexO3 ceramics prepared by Pechini method

Preparation of LaNi_1 − xFe_xO₃, which is one of the candidate materials of solid oxide fuel cell cathode, current collecting layer and interconnect coating was examined with Pechini method and solid state reaction method. Single phase LaNi_1 − xFe_xO₃ with large Ni content has successfully been prepared by low temperature sintering as 750 °C with Pechini method, whereas large amount of raw materials has remained with solid state reaction method by sintering at the same temperature. It can be ascribed to more homogenous cation distribution in raw powder material prior to sintering with Pechini method. It has also been revealed that LaNi_1 − xFe_xO₃ with x lower than 0.3 is thermodynamically unstable in air above 1000 °C. LaNi_0.6Fe_0.4O₃ showed superior property as cathode material with high electrical conductivity, thermodynamic stability and appropriate sintering property.     

First-principle study on catalytic activity of functionalized Ti3C2 MXene as cathode catalyst for Li–O2 batteries

Two-dimensional layered Ti₃C₂, one representative MXene, is notable as promising cathode catalyst for rechargeable lithium-oxygen (Li–O₂) batteries. Using first-principles calculations, we construct cathode electrochemical interface catalytic model to simulate the structural evolution during discharging and charging processes, and the calculated ORR, OER and TOT overpotentials are used to quantitatively assess the catalytic activity of Ti₃C₂ MXene with and without O, F and OH functional groups. Interestingly, we find that the catalytic activity follows such a trend: Ti₃C₂O₂>Ti₃C₂F₂>Ti₃C₂(OH)₂>Ti₃C₂, which suggests that O-terminated Ti₃C₂ MXene has great advantages and potentiality for catalyzing ORR and OER in Li–O₂ batteries. This is caused by Ti₃C₂O₂ surface shows stronger oxidation capability toward O₂²⁻ compared to Ti₃C₂F₂, Ti₃C₂(OH)₂ and Ti₃C₂. The present study may provide a guideline to accelerate ORR and OER reactions of Ti₃C₂ MXene as cathode catalyst in Li–O₂ batteries, with O-terminated group being taken into consideration.     

Molten salt synthesis of Li1 + x (Ni0.5Mn0.5)1 − xO2 as cathode material for Li-ion batteries

Li_1 + x(Ni_0.5Mn_0.5)_1 − xO₂ cathode material for Li-ion batteries has been prepared by a molten salt method using Li₂CO₃ salt. The influences of synthetic temperature and time have been intensively investigated. It is easy to obtain materials with a hexagonal α-NaFeO₂ structure except broad peaks between 20° and 25°. Nickel in Li_1 + x(Ni_0.5Mn_0.5)_1 − xO₂ is oxidized to a trivalent state while manganese maintained a tetravalent state. It is found that the discharge capacities of all samples increase with cycling. The sample prepared at 850 °C for 5 h has a discharge capacity of 130 mAh g^− 1 between 2.5 and 4.5 V versus V_Li+/Li at a specific current of 0.13 mA cm^− 2 after 50 cycles at 25 °C.     

高氯酸消解-ICP-OES测定炭复合磷酸铁锂中的锂、铁、磷

磷酸铁锂是锂电行业主要的产业化原料之一,与传统钴酸锂相比,在比能量、寿命、成本、环境兼容性上有显著优势.以锂离子电池用正极材料炭复合磷酸铁锂为研究对象,采用电感耦合等离子体发生光谱仪(IC P-O ES)同时测定其中的锂、铁、磷含量.对样品消解、谱线选择、仪器工作参数、溶剂效应消除、谱线背景干扰消除、分析方法正确度、精...     

Spectroscopic Study of a Hollow Cathode Discharge Operating at Direct and High Frequency Currents - Temperature Measurements

Spectra excited in a hollow cathode discharge operating at high frequency and direct currents have been studied. Samples (La₂O₃ and Y₂O₃) were placed in the copper hollow cathodes and argon was a carrier gas. The excitation temperatures of Ar I, Ar II, Cu I, Y I, Y II and La II in high frequency and direct current hollow cathode discharges have been determined and compared.     

A Two-Dimensional Porphyrin Coordination Supramolecular Network Cathode for High-Performance Aqueous Dual-Ion Battery

Iodine has great potential in the energy storage, but high solubility of I₃⁻ has seriously delayed its promotion. Benefited from abundant active sites and the open channel, two-dimensional coordination supramolecular networks (2D CSNs) is considered to be a candidate for the energy storage. Herein, a 2D porphyrin-CSN cathode named Zn-TCPP for aqueous iodine dual-ion battery (DIB) shows an excellent specific capacity of 278 mAh g⁻¹, and a high energy density of 340 Wh kg⁻¹ at 5 A g⁻¹, as well as a durable cycle performance of 5000 cycles and a high Coulombic efficiency of 98 %. Molecular orbital theory, UV/VIS, Raman spectroscopy and density functional theory (DFT) calculations reveal charge-transfer interaction between the donor of porphyrin nitrogen and the acceptor of I₃⁻, and computational fluid dynamics (CFD) simulations demonstrate the contribution of 2D layered network structure of Zn-TCPP to the penetration of I₃⁻.     

Synthesis,Crystal Structure and Properties of Li2Cu5(PO4)4

Li₂Cu^II₅(PO₄)₄ has been obtained by various reactions starting from copper or Cu₂O. Crystallization was achieved using I₂ as oxidant and mineralizer. The new orthophosphate crystallizes in space group P$\bar{1}$ , Z = 2, with a = 6.0502(3) Å, b = 9.2359(4) Å, c = 11.4317(5) Å, α = 75.584(2)°, β = 80.260(2)°, γ = 74.178(2)°, at 293 K. Its structure has been determined from X‐ray single‐crystal data and refined to R₁ = 0.022{wR₂ = 0.058 for 4633 unique reflections with F_o > 4σ (F_o)}. From magnetic measurements μ_eff = 1.51 μ_B/Cu and θ_P = –37.4 K have been determined. The Vis/NIR spectrum of aqua‐green Li₂Cu₅(PO₄)₄ shows a single broad band centered around $\bar{1}$ = 12000 cm^–1. Magnetic behavior and spectrum are discussed within the angular overlap model.