锂电池Li／KIBr2—非水体系的研究

本非水电池体系由Ｌｉ负极、多孔石墨电极和电解质溶液组成；电解质溶液由无机溶剂ＰＯＣｌ＿３（或有机溶剂硝基苯）和溶解在该溶剂中的活性物质（ＫＩＢｒ＿２）及支持电解质构成。该电池体系的开路电压为８．５０伏左右，放电性能良好，可望在实际中得到应用。此外，对电池体系的反应机理也作了初步的探讨。     

锂离子电池正极材料LixNi1／3Mn1／3及电化学性能研究CO1／3O2的合成及电化学性能研究

应用以氢氧化物共沉淀为前驱体的高温固相烧结法合成LiNi1/3Mn1/3Co1/3O2正极材料，研究了沉淀温度及烧结过程锂盐投入量对该材料的结构和电化学性能的影响．结果表明，以室温（-20℃）下合成的氢氧化物为前驱体制备的LiNi1/3Mn1/3Co1/3O2具有较好的电化学性能．高温固相烧结会导致部分LiOH损失，因而在合成过程中需加入过量的氢氧化锂，实验表明Li1.08Ni1/3Mn1/3Co1/3O2材料的电化学性能最优．     

Studies on Electrochemical Property of LiFePO4/C as Cathode Material for Lithium Ion Batteries

IntroductionLithium ion batteries are key components of mobiletelephones and portable computers.Among the knownLi-intercalation materials for lithium ion battery cath-odes,LiCoO2,LiNiO2,and LiMn2O4have been stud-ied extensively[1—3].LiCoO2is nowused in c…     

An electrochemical investigation on (MoO<Subscript>3</Subscript>+PVP+PVA) nanobelts for lithium batteries

Molybdenum trioxide (MoO₃) xerogel films modified with poly(vinyl alcohol)+poly(vinyl pyrrolidone) (PVP+PVA) polyblends were obtained by ion-exchange method with sol-gel technique. Investigations were conducted using X-ray “diffractometry”, Fourier transform infrared spectroscopy, and cyclic voltammetry. The results show that the H atoms in polyblend are H-bonded with the O atoms in the Mo=O bonds of MoO₃ xerogel, which effectively shield the electrostatic interaction between MoO₃ interlayer and Li⁺ ions when MoO₃ xerogel is modified by the intercalation of (PVP+PVA). The reversibility of the insertion/extraction of Li⁺ ions is greatly improved by the modification with polyblend of MoO₃ nanocomposite films. MoO₃ and (PVP+PVA) _x MoO₃ (x = 0, 0.5) nanobelts were obtained by a simple hydrothermal process from MoO₃ sol. The electrochemical cells with configuration Li/(LiPF₆+EC+DMC)/MoO₃ modified by (PVP+PVA) were fabricated and their discharge profiles studied.     

Synthesis of silk-like FeS2/NiS2 hybrid nanocrystals with improved reversible oxygen catalytic performance in a Zn-air battery

The development of highly active and stable reversible oxygen electrocatalysts is crucial for improving the efficiency of metal-air battery devices. Herein, an efficient liquid exfoliation strategy was designed for producing silk-like FeS₂/NiS₂ hybrid nanocrystals with enhanced reversible oxygen catalytic performance that displayed excellent properties for Zn-air batteries. Because of the unique silk-like morphology and interface nanocrystal structure, they can catalyze the oxygen evolution reaction (OER) efficiently with a low overpotential of 233 mV at j = 10 mA cm^?2. This is an improvement from the recently reported catalysts in 1.0 M KOH. Meanwhile, the oxygen reduction reaction (ORR) activity of the silk-like FeS₂/NiS₂ hybrid nanocrystals showed an onset potential of 911 mV and a half-wave potential of 640 mV. In addition, the reversible oxygen electrode activity of the silk-like FeS₂/NiS₂ hybrid nanocrystals was calculated to be 0.823 V, based on the potential of the OER and ORR. Further, the homemade rechargeable Zn-air batteries using FeS₂/NiS₂ hybrid nanocrystals as the air-cathode displayed a high open-circuit voltage of 1.25 V for more than 17 h and an excellent rechargeable performance for 25 h. The solid Zn-air batteries exhibited an excellent rechargeable performance for 15 h. This study provided a new method for designing interface nanocrystals with a unique morphology for efficient multifunctional electrocatalysts in electrochemical reactions and renewable energy devices.     

Improved electrochemical properties in the Li3Fe2(PO4)3 by titanium and vanadium doping

Ti⁴⁺ ions were introduced to the VO₄^3- substituted Li₃Fe₂(PO₄)₃ by sol-gel method. Simultaneous substitution of Ti⁴⁺ for Fe³⁺ and VO₄^3- for PO₄^3- in the Li₃Fe₂(PO₄)₃ resulted in a net improvement in the rate capability and cycling performance, as compared with the single Ti⁴⁺ or VO₄^3- substituted compound.     

低共熔混合锂盐相图的绘制及应用

采用热分析法对不同组成的混合锂盐二元体系进行研究, 绘制了混合锂盐体系的步冷曲线和T-x相图, 结果表明体系均为具有最低共熔点的二元体系. LiOH-LiNO3、LiOH-LiCl、LiOH-Li2CO3及LiNO3-LiCl体系的最低共熔点分别为175.7、294.5、418.2及221.6 ℃. 利用低共熔混合物LiNO3-LiOH为锂盐与不同前驱体反应, 制备出了层状结构良好的锂离子电池正极材料LiNiO2、LiNi0.8Co0.2O2及LiNi1/3Co1/3Mn1/3O2. X射线衍射分析表明, 合成的材料具有规整的层状NaFeO2结构, 且XRD衍射峰强度之比I(003)/I(104)>2.0, 电性能测试表明, 在2.7-4.3 V(vs Li/Li+)的电压范围内进行0.1C倍率充放电, LiNiO2、LiNi0.8Co0.2O2、LiNi1/3Co1/3Mn1/3O2首次充电比容量分别达168.0、225.4、194.0 mAh·g-1, 放电比容量分别为138.4、165.8、157.7 mAh·g-1.     

Preparation of spherical spinel LiMn2O4 cathode material for lithium ion batteries

A novel process is proposed for synthesis of spinel LiMn₂O₄ with spherical particles from the inexpensive materials MnSO₄, NH₄HCO₃, and NH₃H₂O. The successful preparation started with carefully controlled crystallization of MnCO₃, leading to particles of spherical shape and high tap density. Thermal decomposition of MnCO₃ was investigated by both DTA and TG analysis and XRD analysis of products. A precursor of product, spherical Mn₂O₃, was then obtained by heating MnCO₃. A mixture of Mn₂O₃ and Li₂CO₃ was then sintered to produce LiMn₂O₄ with retention of spherical particle shape. It was found that if lithium was in stoichiometric excess of 5% in the calcination of spinel LiMn₂O₄, the product had the largest initial specific capacity. In this way spherical particles of spinel LiMn₂O₄ were of excellent fluidity and dispersivity, and had a tap density as high as 1.9 g cm^–3 and an initial discharge capacity reaching 125 mAh g^–1. When surface-doped with cobalt in a 0.01 Co/Mn mole ratio, although the initial discharge capacity decreased to 118 mAh g^–1, the 100th cycle capacity retention reached 92.4% at 25°C. Even at 55°C the initial discharge capacity reached 113 mAh g^–1 and the 50th cycle capacity retention was in excess of 83.8%.     

The effect of Pb and other elements found in recycled polypropylene on the manufacturing of lead-acid battery cases

Polypropylene (PP) is one of the most common plastics used in the manufacturing of lead-acid battery cases, where the recycling of the material has become common practice, being both economically viable and environmentally friendly. During the recycling process, the various components of the spent battery are separated, where the crushed battery case is washed in order to remove any excess acid and lead-containing particles. The plastic components are subsequently melted and extruded into pellets that are then blended with virgin material to injection mold new battery cases and lids. This study showed that a significant amount of lead-containing particles in the form of lead dioxide and lead sulfate remain in the recycled plastic, and are evenly distributed throughout the polymer matrix. TEM studies showed that the particles are less than 1 μm in size and X-ray diffraction analysis of ashed recycled PP samples showed the presence, amongst others, of talc, calcium carbonate, rutile and iron oxide. These compounds come from a range of fillers, flame-retardants, colorants and impurities that originated from the various original battery cases that were recycled. The study showed that modern X-ray fluorescence (XRF) analysis is a quick and reliable method to quantify the amount of the elements found in the plastic and that the concentration of Pb in the plastic can be used as a type of “tracer” to determine the amount of recycled PP used in the manufacturing of a particular battery case. The study also showed that there is possible environmental contamination, in particular with Pb and Br contained in recycled PP during the injection molding process and the burning of the plastic. The Pb- and Br-containing particles are small enough to become air-borne during the burning process of the plastic, resulting in them being part of the soot and other hydrocarbon oils that are emitted. No Pb was observed in the gases emitted during simulated low-temperature injection molding conditions; however, a significant amount of Br was detected in the gases at the lower temperatures. Clear environmental waste classification of the battery case plastic should be done before its final incineration where the amount of trace metals present and its possible contamination to the environment should be considered. Care should also be taken for machine operators who work with the recycled plastic, that no excessive exposure to the halogenated compounds is experienced.     

Electrochemical instability of bis(trifluoromethylsulfonyl)imide based ionic liquids as solvents in high voltage electrolytes for potassium ion batteries

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