Cobalt Sulfide Confined in N-Doped Porous Branched Carbon Nanotubes for Lithium-Ion Batteries

Lithium-ion batteries(LIBs) are considered new generation of large-scale energy-storage devices.However,LIBs suffer from a lack of desirable anode materials with excellent specific capacity and cycling stability.In this work,we design a novel hierarchical structure constructed by encapsulating cobalt sulfide nanowires within nitrogen-doped porous branched carbon nanotubes(NBNTs)for LIBs.The unique hierarchical Co9S8@NBNT electrode displayed a reversible specific capacity of 1310 mAhg-1 at a current density of 0.1 Ag-1,and was able to maintain a stable reversible discharge capacity of 1109 mAhg-1 at a current density of 0.5 Ag-1 with coulombic efficiency reaching almost 100% for 200 cycles.The excellent rate and cycling capabilities can be ascribed to the hierarchical porosity of the one-dimensional Co9S8@NBNT internetworks,the incorporation of nitrogen doping,and the carbon nanotube confinement of the active cobalt sulfide nanowires offering a proximate electron pathway for the isolated nanoparticles and shielding of the cobalt sulfide nanowires from pulverization over long cycling periods.

Selective suppression of rod signal transmission by cobalt ions of low levels in carp retina

Selective suppression of rod signal transmission by cobalt ions was reported in carp retina. Using 10 μmol/L Co2+ , rod-driven horizontal cells were hyperpolarized and light responses were completely suppressed in super-fused, isolated retina, while cone-driven horizontal cells were almost unaffected. Similarly, scotopic electroretino-graphic b-wave was suppressed by 10 μmol/L Co2+ , while the photopic b-wave remained unaffected. Furthermore, the glutamate-isolated receptor potential (PIII) was not altered by low Co2+ under dark-adapted conditions. Other di-valent ions with high affinity to calcium channels, such as cadmium and manganese ions, did not show similar suppres-sive effect on the rod horizontal cells. When rod horizontal cells were hyperpolarized by 10 μmol/L Co2+ , the use of 3 mmol/L glutamate caused a significant depolarization of the cells, indicating that Co2+ application did not impair the ability of these cells to respond to glutamate. On the other hand, application of 200 μmol/L β-hydroxyaspartate, a glu-tamate transport blocker, mimicked the effect of low Co2+ , suggesting a possibility that the low Co2+ effect might be related to a blockade of glutamate uptake by rods.

Electrodeposited Cobalt-Iron Alloy Thin-Film for Potentiometric Hydrogen Phosphate-Ion Sensor

A cobalt-iron alloy thin-film electrode-based electrochemical hydrogen-phosphate-ion sensor was prepared by electrodepositing on an Au-coated Al2O3 substrate from an aqueous solution of metal-salts. The use of a cobalt-iron alloy electrode greatly improved the hydrogen-ion sensor response performance, i.e., the sensor worked stably for more than 7 weeks and showed a quick response time of several seconds. Among the cobalt and iron alloy systems tested, the electrodeposited Co58Fe42 thin-film electrode showed the best EMF response characteristics, i.e., the sensor exhibited a linear potentiometric response to hydrogen-phosphate ion at the concentration range between 1.0 × 10–5 and 1.0 × 10–2 M with the slope of –43 mV/decade at pH 5.0 and at 30℃. A sensing mechanism of the Co-based potentiometric hydrogen-phosphate ion sensor was proposed on the basis of results of instrumental analysis.

Electrochemical properties of some cobalt antimonides as anode materi-als for lithium- ion batteries

Some cobalt antimonides have been prepared and studied as the candidate anodematerials for lithium ion batteries. Reversible capacities of 424,423 and 546 mA.h.g^(-1) weremeasured at the first cycle for as-solidified CoSb_2, CoSb_3 and annealed CoSb_3 respectively. A lowlithium ions diffusion coefficient in the order of 10^(16) m^2.s^(-1) was estimated from thecoulometric titration measurements in the annealed CoSb_3 electrode. It was found that theelectrochemical properties of fine powders are significantly better than coarse powders. However theSEM picture shows that the nano-sized CoSb_3 powders gathered to larger granules, which worsenssomewhat the capacity retention of the nano-sized materials, although the volume capacities of theannealed and ball milled CoSb_3 remain near twice of that of graphite after 50 cycles.

Recycling of Cobalt by Liquid Leaching from Waste 18650-Type Lithium-Ion Batteries

In this work, we recover cobalt from waste 18650-type lithiumion batteries by acid leaching. The cathode material is completely dissolved, after leaching waste batteries by using 10 mol/L industrial sulfuric acid at 70℃ for 1 h. The rate of cobalt leaching is nearly 100%. Removal of sodium carbonate, iron, aluminum and other impurities from the leaching solution was well performed by adjusting the pH to 2-3 with stirring vigorously. Finally, under the conditions of 55℃-60℃ of 240 A/m2 current density, electrodeposition current efficiency was 90.01%, the quality of the electrical output achieved cobalt 1A standard electrolytic cobalt, cobalt until greater than 90% yield. The process is easy and suitable for large-scale lithiumion batteries used in the recovery of valuable metals.

Stabilising Cobalt Sulphide Nanocapsules with Nitrogen-Doped Carbon for High-Performance Sodium-Ion Storage

Conversion-type anode materials with a high charge storage capability generally su er from large volume expansion, poor electron conductivity, and sluggish metal ion transport kinetics. The electrode material described in this paper, namely cobalt sulphide nanoparticles encapsulated in carbon cages(Co9S8@NC), can circumvent these problems. This electrode material exhibited a reversible sodium-ion storage capacity of 705 mAh g^-1 at 100 mA g^-1 with an extraordinary rate capability and good cycling stability. Mechanistic study using the in situ transmission electron microscope technique revealed that the volumetric expansion of the Co9S8 nanoparticles is bu ered by the carbon cages, enabling a stable electrode–electrolyte interface. In addition, the carbon shell with high-content doped nitrogen significantly enhances the electron conductivity of the Co9S8@NC electrode material and provides doping-induced active sites to accommodate sodium ions. By integrating the Co9S8@NC as negative electrode with a cellulose-derived porous hard carbon/graphene oxide composite as positive electrode and 1 M NaPF6 in diglyme as the electrolyte, the sodium-ion capacitor full cell can achieve energy densities of 101.4 and 45.8 Wh kg^-1 at power densities of 200 and 10,000 W kg^-1, respectively.

基于X射线光电子能谱的NCM正极材料中过渡金属化学态判断和定量分析:挑战及解决方法

X射线光电子能谱(XPS)在锂离子电池镍钴锰酸锂(LiNi_(x)Co_(y)Mn_(1-x-y)O_(2),NCM)正极材料的分析中有着重要应用,然而NCM中Ni、Co、Mn过渡金属主峰与俄歇峰相互重叠使这三种元素的化学态识别和定量分析变得困难。以LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)为例,分析了XPS谱图中过渡金属主峰与俄歇峰的干扰问题,并提出一个基于非线性最小二乘拟合的算法对相互重叠时的过渡金属2p峰进行分峰拟合。通过比较不同化学态的Ni/Co/Mn参考样品,选取Ni(OH)_(2)、NiOOH、LiCoO_(2)、MnO_(2)作为拟合参考谱图。与常规的高斯/洛伦兹拟合方法相比,建立的非线性最小二乘拟合方法无需手动调整拟合参数,使得XPS谱图拟合过程不依赖于操作者,可重复性得到提高,并验证了这种拟合方法在NCM811正极材料XPS谱图分析中的有效应用,将过渡金属的主峰和其他元素的俄歇峰进行分离,为Ni、Co、Mn过渡金属主峰与俄歇峰相互重叠的化学态识别和定量分析难题提供了可参考的解决方案。

无钴富锂层状氧化物的结构调控和电化学性能研究

采用碳酸盐前驱体共沉淀-高温固相法制备无钴富锂层状氧化物正极材料,研究了组分调节对材料阳离子排布和电化学性能的影响。对材料进行不同尺度的形貌和结构表征以及电化学测试,研究结果表明:降低Li摩尔分数可以减小材料的一次颗粒粒径,在不影响材料富锂相摩尔分数的前提下减小了类Li_(2)MnO_(3)晶畴的尺寸,并且增大了材料的Li^(+)/Ni^(2+)混排程度;小尺寸的类Li_(2)MnO_(3)晶畴可以提高晶格氧氧化活性和材料的充电容量;Li^(+)/Ni^(2+)混排的增加可以提高晶格氧还原活性和材料的放电容量,并抑制循环过程中的电压衰减。

CoFe_2O_4-Graphene Nanocomposites Synthesized through An Ultrasonic Method with Enhanced Performances as Anode Materials for Li-ion Batteries

Co Fe2O4-graphene nanosheets(Co Fe2O4-GNSs) were synthesized through an ultrasonic method, and their electrochemical performances as Li-ion battery electrode were improved by annealing processes. The nanocomposites obtained at 350 °C maintained a high specific capacity of 1,257 m Ah g-1even after 200 cycles at 0.1 A g-1. Furthermore,the obtained materials also have better rate capability, and it can be maintained to 696, 495, 308, and 254 m Ah g-1at 1, 2,5, and 10 A g-1, respectively. The enhancements realized in the reversible capacity and cyclic stability can be attributed to the good improvement in the electrical conductivity achieved by annealing at appropriate temperature, and the electrochemical nature of Co Fe2O4 and GNSs during discharge–charge processes.

CoFe_2O_4/carbon nanotube aerogels as high performance anodes for lithium ion batteries

High-performance lithium ion batteries(LIBs) require electrode material to have an ideal electrode construction which provides fast ion transport, short solid-state ion diffusion, large surface area, and high electric conductivity. Herein, highly porous three-dimensional(3D)aerogels composed of cobalt ferrite(CoFe_2O_4, CFO) nanoparticles(NPs) and carbon nanotubes(CNTs) are prepared using sustainable alginate as the precursor. The key feature of this work is that by using the characteristic egg-box structure of the alginate, metal cations such as Co^(2+)and Fe^(3+) can be easily chelated via an ion-exchange process, thus binary CFO are expected to be prepared. In the hybrid aerogels, CFO NPs interconnected by the CNTs are embedded in carbon aerogel matrix, forming the 3D network which can provide high surface area, buffer the volume expansion and offer efficient ion and electron transport pathways for achieving high performance LIBs. The as-prepared hybrid aerogels with the optimum CNT content(20 wt%) delivers excellent electrochemical properties, i.e., reversible capacity of 1033 mAh g^(-1) at 0.1 A g^(-1) and a high specific capacity of 874 mAh g^(-1) after 160 cycles at 1 A g^(-1). This work provides a facile and low cost route to fabricate high performance anodes for LIBs.

A kinetic study of the electron-transfer in the reaction of tribenzylchlorotin with[CoW_(12)O_(40)]^(5-)

A kinetic study of the electron-transfer in the reaction of tribenzylchlorotin with potassium 12-tungsto cobalt （Ⅲ） ate ion, Ks[CoW12O40], abbreviated as Co（III）W, has been performed in different solvents. The studies were carried out in methanol, ethanol, acetonitrile and acetic acid/water. The rate constants, reaction rates and activation parameters were calculated. Our findings show that the rate of disappearance of the Co（Ⅲ） is pseudo-first order. The kinetic data is strongly affected by used solvents. The maximum and minimum rate constants were achieved in the ethanol and acetic acid/water （70/30） as a solvent, respectively. In all of the used solvents, negative value of activation entropies was observed, but negative activation enthalpies are observed in methanol, ethanol and acetonitrile. The reaction rate is increased with increase of Co（Ⅲ） concentration. ？2009 Fatemeh E Bamoharram. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Mid-Term Review of ADEPT Metal-On-Metal Hip Prosthesis. Functional, Radiological and Metal Ion Analysis

Background: There is much interest regarding metal-on-metal implants in medical and general media. Much of this has been regarding failure of specific implant systems and metal ion toxicity. We present our early mid-term experience of the ADEPT metal-on-metal system which has both modular and non-modular hip options. Methods: Functional assessment, blood metal ion quantification, and radiographic analysis were performed for the modular and non-modular ADEPT variants. Fifty implants were implanted with a mean follow up time of 28 months. Unpaired t-tests were used to compare modular and resurfacing groups, standardised hip scores were used to compare function to conventional total hip arthroplasty. Results: Metal ion levels were significantly higher in modular prostheses compared to resurfacing implants, but not at “harmful” levels (as determined by a previous metal-on-metal implant recall). Functional outcomes were excellent and revision rates were lower than expected. Conclusions: At our institution we have good outcomes with the ADEPT hip prosthesis. Though patient selection and implant position are crucial, poor performance of metal-on-metal hip replacements is implant specific.

Synthesis and electrochemical characterization of layered Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 cathode materialfor Li-ion batteries

Layered LiNi1/3Co1/3Mn1/3O2 materials were synthesized using a nickel-cobalt-manganese carbonate precursor obtained by chemical co-precipitation. The [Ni1/3Co1/3Mn1/3]CO3 precursor and the LiNi1/3Co1/3Mn1/3O2 powders were characterized by X-ray diffraction（XRD） and scanning electron micrograph（SEM）. The SEM analysis shows that these particles possess uniform and spherical morphology. The electrochemical properties of the (LiNi1/3-)(Co1/3Mn1/3O2) cathode material for rechargeable lithium-ion batteries such as the galvanostatic charge-discharge performance and cyclic voltammetry（CV） were measured. The results show that an initial discharge capacity of 190.29mA·h·g-1 is obtained in the voltage range of 2.54.6V and at a current rate of 0.1C at 25℃.The discharge capacity increases linearly with the increase of the upper cut-off voltage limit.

Synthesis and Electrochemical Property of Calcium Doped LiNi0.8Co0.2O2 Solid Solution

A divalent ion doped LiNi0.8Co0.2O2 solid solution, LiNi0.79Co0.20Ca0.01O2, was synthesized in air at 720℃. The structure and electrochemical property as cathode material of lithium ion batteries were measured by XRD and charge-discharge system. The solid solution showed high capacity and good cycle-ability. The second discharged capacity reached 190 mAh穏-1 at the current density of 100 mA穏-1.

纳米羟基磷灰石稳定悬浮体系的制备及其钴吸附性能

为改善纳米羟基磷灰石(HAP)作为重金属离子吸附剂的吸附性能,模拟了人体中聚合物诱导的类液体前驱体矿化过程,利用聚丙烯酸(PAA)作调控剂通过水热法制备出了稳定悬浮的纳米HAP体系,探究了PAA的COOH与Ca的物质的量之比(R)、反应pH、水热温度对制备的纳米HAP的影响。在优化出的合成条件(R=1、pH=9.00、180℃)下制备的纳米HAP是由细小颗粒组成的梭形结构,能够在保持几十纳米粒径尺寸的同时稳定悬浮。继而探究了吸附时间、初始金属离子浓度、吸附环境的pH、悬浮性对纳米HAP的Co^(2+)吸附性能的影响。吸附结果表明吸附动力学符合准二级动力学模型,吸附过程包括表面吸附与粒子内扩散。Freundlich、Langmuir模型线性方程拟合结果与实验结果均具有较高契合度,对应的Langmuir模型线性拟合最大吸附量为229.358 mg·g^(-1)。对Co^(2+)去除率随吸附环境pH(6.48~9.00)的升高而增大,主要吸附机制为表面配位反应。制备的纳米HAP悬浮液吸附量明显优于非悬浮的对照纳米HAP。

不同正极材料的大容量锂离子电池热失控实验研究

为探究不同正极材料大容量锂离子电池的热失控特性,针对不同荷电状态(SOC)下相同容量的不同正极材料大容量52 Ah磷酸铁锂电池(LFP)和53 Ah三元锂离子电池(NCM)的热失控进行实验,通过热失控行为、热失控特征参数等参数对比二者的宏观行为与特征。实验结果表明:NCM热失控比LFP更剧烈;SOC越大,NCM与LFP更易发生热失控且热失控更剧烈,NCM热失控对SOC的变化更敏感。

碳@硒化钴/还原氧化石墨烯锂离子电池负极材料的制备及性能研究

以葡萄糖和石墨烯为碳源,通过简便的水热工艺成功制备了一系列具有多孔结构的C@CoSe/rGO复合材料。电化学测试结果表明,在200 mA/g电流密度下进行150圈循环测试后,C@CoSe/rGO-2复合材料的可逆比容量为751 mAh/g;在1 000 mA/g和2 000 mA/g大电流密度下进行150圈循环测试,其比容量仍可达525 mAh/g和285 mAh/g。该工作提供了一种简单的方法用于制备比容量高、倍率性能好且循环稳定的锂离子电池负极材料。

高锰酸钾改性凹土对钴离子的吸附性能研究

首先,测量了不同浓度下钴离子溶液的吸光度,并通过线性拟合得到了相关系数为0.999的标准曲线.随后,采用酸性高锰酸钾改性法研究了GK-2H型凹土对钴离子的吸附能力.结果表明,经改性后的凹土对钴离子的吸附能力明显优于改性前的凹土吸附能力,特别是在高锰酸钾溶液pH值为2.44、浓度为0.06 mol/L时的吸附效果最佳,高达20.9%.最后,利用XRD、SEM、TEM和IR等方法对其进行检测,发现:改性后的凹土不但结构分散性好,而且表面也更圆润、杂质少.

碳量子点双光法检测溶液中的钴离子

发现合成的碳量子点加入钴离子后溶液变成绿色,在650 nm处有紫外吸收,适用检测范围为0.8~35 mmol/L,方程式为y=0.007 46x+0.219 51,R^(2)=0.998 2;当钴离子浓度为0.04~6 mmol/L能猝灭碳量子点的荧光,浓度的对数与F_(0)/F比值呈现线性相关系数R^(2)=0.996,线性方程为:y=0.565 3x+1.739 6。因此,当钴离子浓度为0.8~6.0 mmol/L时,此碳量子点能达到双光法检测溶液中的钴离子,通过加标回收自来水样验证双光法检测有效。

双重改性三元正极材料及其性能研究

为提高三元正极材料LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(NCM523)的可逆比容量和循环稳定性,通过表面包覆聚并苯(PAS)复合钾氯共掺杂对NCM523材料进行双重改性,利用XRD､SEM､TEM等分析方法和恒电流充放电性能测试,研究了不同PAS包覆量复合K､Cl共掺杂NCM523材料的结构､形貌和电化学性能。结果表明,2%PAS包覆复合1%K和Cl共掺的NCM523材料在0.1 C首次放电容量为209.5 mAh/g;1 C倍率下充放电循环100次后放电容量保持率比未改性的NCM523提高了19%;5 C倍率下的放电比容量为158.1 mAh/g,比未改性的NCM523提高了13%。