Mg~(2+)、Zr~(4+)离子掺杂对Li_4Ti_5O_(12)电化学性能的影响

以固相反应法合成了尖晶石型Li4Ti5O12电极材料,进行了金属离子掺杂以提高其导电性及综合性能,以适应用于大电流充放电的目的。采用XRD、室温恒流充放电循环、交流阻抗和循环伏安等测试手段,考察了A位掺杂Mg(Li4-xMgxTi5O12,x=0.15),B位掺杂Zr(Li4ZrxTi5-xO12,x=0.15)对Li4Ti5O12结构和电化学性能的影响。结果表明:掺杂少量的Mg2+、Zr4+未引起材料结构的变化,明显降低了Li4Ti5O12电荷转移阻抗,使导电性得到有效提高。0.1 C放电倍率下放电,未掺杂及掺杂Mg2+、Zr4+的Li4Ti5O12首次放电容量分别为159.8、144.9、161.2mAh/g,循环40次后,容量分别保持为113.8、130.6、133.6 mAh/g。与未掺杂的Li4Ti5O12相比,掺杂后的电极材料极化减小、循环容量及稳定性提高。     

Performance of a magnesium–lithium alloy as an anode for magnesium batteries

In this work, we describe an evaluation of an Mg–Li alloy (Li: 13 wt %) for possible use in magnesium primary reserve batteries. Higher OCP for the Mg–Li alloy have been observed in 2 M MgCl₂ and MgBr₂ electrolyte. The corrosion rate of the Mg–Li alloy is found to be in the order: MgCl₂ < Mg(COOCH₃)₂ < MgSO₄ < MgBr₂ < Mg(ClO₄)₂. Mg–Li alloys exhibit higher (81%) anodic efficiencies even when the current density is increased to 8.6 mA cm ^–2. It has been observed that Mg–Li/MgCl₂/CuO cells offer higher operating voltage and capacity than those with the conventionally used Mg–Al alloy.     

Polymer and nanobelt derived nanomaterials: opening doors to revolutionary stadia

ABSTRACT

The state-of-the-art article presents concepts of nanobelt nanofiller, inimitable properties of derived polymeric nanocomposite, applications, and outlook on challenges to gain next generation high-performance materials. Nanobelt is a one-dimensional nanostructured nanomaterial. Owing to minuscule size and high surface area, nanobelt possesses unique structural, optical, electronic, mechanical, and thermal characteristics. Nanobelt exists in various forms such as carbon nanobelt, polymer nanobelt, and inorganic. These nanobelts have been used to develop polymer/nanobelt nanocomposites. Homogeneous dispersion of nanobelt in polymer matrices is desirable to enhance the characteristics of polymer/nanobelt nanocomposite. Consequently, innovations in design, fabrication, and properties of various polymer/nanobelt nanocomposite are summarized. Applications of polymer/nanobelt nanocomposite are reviewed for Li-ion battery, supercapacitor, sensor, membrane, and biomedical arenas.     

离网型太阳能光伏发电系统设计研究

离网型太阳能光伏发电系统是太阳能光伏发电系统的重要组成。它具有灵活度高、分布广、项目成本低等优点。本文主要对现有离网光伏发电系统设计过程进行分析。     

树脂包覆对石墨化中间相沥青炭微球电化学性能的影响

以中间相沥青炭微球(SSGMCMB)为核、酚醛树脂(PR)热解炭为壳，采用浸渍一固化一炭化手段制备出树脂热解炭包覆SSGMCMB复合材料，并对其电化学性能进行了研究。通过SEM、XRD、恒电流充放电测试等手段研究了不同树脂包覆量对该复合材料的形态、结构及其电化学行为的影响，结果表明：树脂热解炭对SSGMCMB有较好的包覆作用，保持了SSGMCMB的球形形态，有利于锂离子的嵌入／脱出反应，对其电化学性能有一定的提高，改进了酚醛树脂热解炭有较大电压滞后的问题。     

Electrochemical investigation of LiNi0.5Mn1.5O4 thin film intercalation electrodes

This work provides kinetic and transport parameters of Li-ion during its extraction/insertion into thin film LiNi_0.5Mn_1.5O₄ free of binder and conductive additive. Thin films of LiNi_0.5Mn_1.5O₄ (0.2 μm thick) were prepared on electronically conductive gold substrate utilizing the electrostatic spray deposition technique. High purity LiNi_0.5Mn_1.5O₄ thin film electrodes were observed with cyclic voltammetry, to exhibit very sharp peaks, high reversibility, and absence of the 4 V signal related to the Mn³⁺/Mn⁴⁺ redox couple. The electrode subjected to 100 CV cycles of charge/discharge delivered a capacity of 155 mAh g⁻¹ on the first cycle and sustained a good cycling behavior while retaining 91% of the initial capacity after 50 cycles. Kinetics and mass-transport of Li-ion extraction at LiNi_0.5Mn_1.5O₄ thin film electrode were investigated by means of electrochemical impedance spectroscopy. The apparent chemical diffusion coefficient (D_app) value determined from EIS measurements changed depending on the electrode potential in the range of 10⁻¹⁰-10⁻¹² cm² s⁻¹. The D_app profile shows two minimums at the potential values close to the peak potentials of the corresponding cyclic voltammogram.     

基于充电方式的锂电池SOC 校准和估计方法

荷电状态(SOC)是动力锂电池的重要参数.针对安时法估计锂电池SOC存在累积误差,其他估计算法复杂度较高的问题,提出一种工程实用的SOC估计方法.该方法通过分析电池特性并结合安时法,建立了SOC初始值、总容量和累积误差的校准方法.通过建立终端电压与SOC之间的映射关系,利用恒流、恒压不同充电阶段的电池特性,实现了电池系统在一个放电周期内的SOC高精度估计.实验表明,该方法能够使得SOC的估计误差在5%以内.     

基于电动汽车电池管理系统模型的CANopen协议研究

针对电动汽车电池管理系统的数据通信问题,本文提出了基于CANopen协议的实现方法,研究了符合CANopen协议标准CiA301的PDO、SDO、SYNC、NMT报文、心跳报文及符合CANopen设备子协议CiA418的对象字典,并进行了软件编程和实验测试,结果表明本方法适用于电动汽车电池管理系统.     

燃料电池与碳纤维之应用

介绍了以氢气为主要反应物的燃料电池作为替代性能源无污染和高效率的特点,燃料电池的应用领域、电池种类、工作原理和组成元件,以及逢甲大学研发之燃料电池气体扩散层技术。测试结果表明:当Load0.5V时,该自制的新型气体扩散层电流密度可达1026.4～1149.6mA/cm,而商用气体扩散层电流密度为941.6mA/cm;自制气体扩散层功率密度可达600mW/cm,而商用气体扩散层功率密度为511.2mW/cm,均高过商用气体扩散层。     

利用蓄电池废硫酸和硼泥制备高品质氢氧化镁

利用废铅酸蓄电池中的废硫酸作为浸取剂,对硼泥中的镁进行回收并制备出高品质的氢氧化镁产品。实验得出了酸浸硼泥的最佳工艺条件：酸浸温度为80℃;酸浸时间为30 min;酸用量为硫酸与硼泥质量比为1.2∶1。利用不同金属水解pH的不同,将酸浸过程中从硼泥和废硫酸中引入的杂质依次去除,得到精制硫酸镁溶液。由精制硫酸镁制取氢氧化镁的工艺条件为：常温下,沉淀剂为氨水,反应终点pH为11,反应时间为2 h,反应物在50℃下陈化12 h,过滤、洗涤后105℃烘干。实验考察了不同沉淀剂对氢氧化镁形貌的影响。所得氢氧化镁纯度在97%以上,粒径在0.1～1μm之间,各项指标均优于中国化工行业标准。