Carbonaceous mesophase spherule/activated carbon composite as anode materials for super lithium ion capacitors

A series of carbonaceous mesophase spherule/activated carbon composites were prepared as anode materials for super lithium ion capacitors using carbonaceous mesophase spherules as the core materials and pitch as the active carbon shell precursor.The structures of the composites were examined by scanning electron microscopy and X-ray diffractometry.The electrochemical performance was investigated in electric double layer capacitor and half-cell.The results show that,the composite exhibits good performance in...     

Synthesis and electrochemical characterization of LiNi0.78Co0.2Al0.02O2 cathode material in a novel co-precipitation method

LiNi0.78 Co0.2 Al0.02O2 cathode materials were prepared with a novel co-precipitation method followed by heat-treating. The properties of the materials were characterized. XRD patterns showed that no secondary phase appeared and the hexagonal lattice parameter c of LiNi0.rsCoo.2AI~0202 was larger than that of LiNi0.8Co0.2O2. The SEM images indicated that the powders of the material were submicron size. The results of the ICP-AES analysis proved that elemental compositions of the material were similar to those of the targeted one. Cyclic voltammetry （3.0- 4. 2 V） illustrated that the new material had good lithium-ion intercalation/de-intercalation performance. The results of galvanostatic cycling showed that the initial specific discharge capacity of the prepared material was 181.4 mAh/g, and the specific discharge capacity was 177.3 mAh/g after 100 cycles （0. 2C, 3.0 - 4. 2 V, vs. Li^＋/Li） with the capacity retention ratio of 97.7%.     

除湿型空调中气泡泵的试验研究

在以气泡泵原理自循环的液体除湿型空调系统中，气泡砂进一个关键。针对以氯化锂水溶液为除湿剂、利用燃气加热实现无泵循环的系统进行了理论和试验研究。搭建了气泡泵试验装置，测定了气泡泵性能参数，实验结果对气泡泵的设计具有指导意义。     

废旧磷酸铁锂电池正极活性材料与集流体的分离

在废旧磷酸铁锂电池回收的工艺流程中,研究高温煅烧与有机溶剂对正极活性材料的分离效果。正极片在500℃的N2氛围下加热5 h,活性材料的分离率(η)达到95.98%。在60℃固液比(g/mL) 1:25的条件下,将表面积0.25 cm~2的正极片浸泡在碳酸丙烯酯(PC)溶剂中超声120 min,活性材料的η达到68.6%。相比传统的处理方法,这两种方法降低了成本,避免因采用强酸强碱而产生二次污染。     

基于CFD的锂电池温度场仿真

建立了锂电池热特性的三维数学模型.将结构复杂的锂电池当成一个整体获取其热物理参数,同时采用分段线性插值的方式考虑比热容、导热系数随电池的SOC(荷电状态)的变化.利用商业CFD软件FLUENT对锂/二氧化硫单体电池进行了三维温度场仿真计算,分析了电池热物理参数的变化、放电电流以及散热环境对电池温度分布的影响.     

一种基于单片机的智能充电器设计

介绍一种基于单片机的智能充电器的硬件和软件实现。该充电器可以实时采集和计算电池的参数，并进行智能控制，还可以通过串口和上位机进行通讯并进行实时显示，根据不同的电池调整充电策略。实验证明，该设计具有数字化、智能化、通用化和低功耗的特点。     

柔性聚合物电解质的制备及其电化学性能

以不同质量比的丙烯酸甲酯(MA)和丙烯腈(AN)为单体,聚乙烯醇(PVA)为分散剂,采用绿色环保的改性乳液聚合法制得聚合物乳液,将聚合物乳液流延涂布制得柔性聚合物膜,进一步采用电解液浸润法制得系列柔性聚合物电解质膜(S1、S2、S3和S4)。通过傅里叶红外光谱仪(FTIR)、扫描电镜(SEM)、力学性能测定、热分析、交流阻抗(EIS)和充放电测试对材料的物理化学性能进行了表征。结果表明:当m(MA)∶m(AN)=23∶2(S2)时,聚合物膜的抗拉强度为14.3 MPa,断裂伸长率为248%,25℃时的离子电导率为0.95m S/cm。分别以LiCoO_2为正极、金属锂为负极,天然石墨为正极、金属锂为负极制备CR2032扣式锂离子电池并测试其循环伏安性能和充放电性能,4次循环伏安测试发现峰电位均无明显变化,0.1 C倍率下,首次放电比容量分别为142和307 mA·h/g,50次循环后分别为135和323 m A·h/g,1.0 C倍率下,LiCoO_2的放电比容量为134.3 mA·h/g,说明所制备的材料具有较好的电化学性能。     

Enhanced wettability and thermal stability of polypropylene separators by organic–inorganic coating layer for lithium‐ion batteries

Organic–inorganic coating polypropylene separators were developed by introducing SiO₂ nanoparticles through sol–gel process, where polydopamine was used as an intermediate layer. Scanning electron microscopy results showed the coating layers have highly porous structure, which was beneficial for liquid electrolyte uptake. Compared with pristine polypropylene separator, the ceramic separators showed improved thermal stability, higher ionic conductivity, and lower interfacial impedance. The cells employing the ceramic separators delivers excellent discharge capacity (retention = 75%) and coulombic efficiency up to 98% at 2 °C rate after 100 cycles. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46478.     

Thermal regimes of Li‐ion conductivity in β‐eucryptite

While it is well‐established that ionic conduction in lithium aluminosilicates proceeds via hopping of Li ions, the nature of the various hoping‐based mechanisms in different temperature regimes has not been fully elucidated. The difficulties associated with investigating the conduction have to do with the presence of grains and grain boundaries of different orientations in these usually polycrystalline materials. Herein, we use electrochemical impedance spectroscopy (EIS) to investigate the ion conduction mechanisms in β‐eucryptite, which is a prototypical lithium aluminosilicate. In the absence of significant structural transitions in grain boundaries, we find that there are three conduction regimes for the one‐dimensional ionic motion along the c axis channels in the grains, and determine the activation energies for each of these temperature regimes. Activation energies computed from molecular statics calculations of the potential energy landscape encountered by Li ions suggest that at temperatures below 440°C conduction proceeds via cooperative or correlated motion, in agreement with established literature. Between 440°C and 500°C, the activation barriers extracted from EIS measurements are large and consistent with those from atomistic calculations for uncorrelated Li ion hopping. Above 500°C the activation barriers decrease significantly, which indicates that after the transition to the Li‐disordered phase of β‐eucryptite, the Li ion motion largely regains the correlated character.     

Elimination of boron and lithium coexisting in geothermal water by adsorption-membrane filtration hybrid process

Direct release of geothermal waters to the environment may cause some damages to some plants because they contain toxic species such as boron, arsenic, fluoride etc. along with valuable minerals including lithium. In this study, a hybrid process combining adsorption and membrane filtration was used to separate boron and lithium simultaneously from geothermal water. According to the results obtained, separation efficiencies for lithium and boron from geothermal water were 100% and 83% using boron selective ion exchange resin Dowex XUS-43594.00 and lithium selective λ-MnO₂ adsorbent, respectively. The kinetic data of lithium and boron adsorption have been evaluated using pseudo-first order and pseudo-second-order kinetic models.