基于锂盐的新型锂电池电解质研究进展

随着新能源汽车、可携带式电源和储能等领域的快速发展, 人们对锂电池性能提出了更高的要求, 高性能锂离子电池的重要性日益突出。电解质是锂离子电池的重要组成部分, 对于电池的输出电压、倍率性能、适用温度范围、循环性能和安全性能等有着重要的影响。而锂盐作为液体电解质(电解液)的关键组分, 是决定电解液性能的重要因素。电解液中不同种类的锂盐及其在溶液中不同的溶剂化状态, 会对电极/电解液界面的成膜性能和锂离子的迁移行为等产生重要影响, 进而显著影响电解液的电化学性能。本文介绍了近年来新型电解质锂盐的性质特点和在不同种类电池中的应用。同时, 单一的锂盐不能完全满足锂电池对电解液的要求, 因而人们尝试采用复合锂盐使功能更完善, 催生了多盐体系电解液。多盐体系电解液在拓宽电池工作温度、抑制金属离子溶出和提高倍率性能等方面表现出明显优势。同时, 借助于浓度的提升改变锂离子的溶剂化结构, 研究人员提出了高浓度电解液。高浓度电解液在防止石墨剥离、拓宽电解液电化学窗口、抑制铝箔腐蚀和提高金属锂沉积/溶出性能等方面具有明显优势。并且, 本文重点讨论了这两种电解液对电池性能提升的机理。最后, 对锂盐基电解液尤其是这两类新型电解液的发展趋势和应用前景进行了展望。     

活塞销冲连皮工艺与模具设计

研究了活塞销连皮加工采用冲压技术代替钻削加工的理论可行性,通过对冲连皮过程材料所受应力及冲孔过程内孔表面质量状况的分析,制定了冲连皮工艺,设计了模具,阐述了采用冲连皮工艺对活塞销产品的形位尺寸及质量的影响;通过冲连皮工艺试验及批量生产,证明采用冲连皮工艺能够应用于活塞销加工过程;并提出了采用冲连皮工艺目前存在的问题及今后的发展方向。     

桑宁茶降血糖作用研究

以常规降糖药格列本脲(优降糖)为阳性对照,通过对正常小鼠和糖尿病小鼠进行葡萄糖耐量试验(GTT)及降血糖治疗试验,研究了桑宁茶的降血糖作用。结果表明,桑宁茶对高糖负荷后的小鼠的血糖值有非常好的稳定作用,能将小鼠的血糖值控制在正常范围内,且效果优于格列本脲;在0.675～2.70g/kg的给药范围内,桑宁茶能明显改善糖尿病小鼠的高血糖症状,具有良好的降血糖作用,并且呈显著的剂量-效应关系。     

锂离子电池负极材料多孔Li4Ti5O12/C的制备与表征

将钛源、锂源和碳源三种化合物一起球磨湿混成均匀浆料,再依次经过喷雾干燥和高温煅烧制得晶粒表面包覆纳米碳层的多孔球形钛酸锂(Li4Ti5O12)材料.通过XRD、SEM、TEM、BET和电化学性能测试等分析手段表明,合成出的Li4Ti5O12/C材料为纳米一次粒子(晶粒)组成的球形二次粒子(颗粒),具有较大的比表面积,达到39.5 m2/g;在0.1C、1.0C和5.0C倍率下的首次放电比容量分别达到172.2、168.2和153.6 mAh/g,并表现出优良的循环性能.晶粒表面包覆碳的多孔Li4Ti5O12材料具有明显的高倍率性能和循环稳定性优势.     

KHR32C高温炉管焊接

通过对KHR32C高温炉管焊接接头常温拉伸试验、金相分析、高温拉伸等试验,证明在焊接过程中要采用小电流多层多道焊,严格控制焊接线能量和焊接层间温度,从而保证高温炉管的焊接质量。     

发动机电子控制技术现状及发展趋势

从发动机控制功能、硬件应用、检测手段、设计方法等方面.时发动机电子控制技术现状和发展趋势作了系统阐述.     

尖晶石LiMn2O4作为锂离子正极材料的研究与开发

介绍了LiMn₂O4材料的各种制备技术,并归之于固相法和液相法两大类,简述了当前LiMn₂O₄材料研究存在的主要问题及抑制LiMn₂O₄容量衰减的思路和解决方案.     

Investigation of Urea-Melamine-Formaldehyde (UMF) resin penetration in Medium-Density Fiberboard (MDF) by High Resolution Confocal Laser Scanning Microscopy

A confocal laser scanning microscope (CLSM) was used to investigate the distribution and penetration of urea-melamine-formaldehyde (UMF) resin in the fiber when injected through blowline blending in a medium density fiberboard (MDF) pilot plant. Samples were prepared with respect to industrial parameters and were collected at the dryer’s end. The samples were later dyed in a Dye Star-Brilliant Red solution (0.01%) and rinsed with distilled water to remove excess. The samples were scanned with the CLSM to build three-dimensional reconstructions of MDF fiber cross-sections. With proper lenses and optimized CLSM settings, it was possible to obtain fiber reconstructions with a resolution greater than the laser wave length (514 nm). The Zeiss CLSM built-in software image analyzer enabled to rebuild them in rotation on any of the three axes with up to 64 images per rotation. The resin penetration sites were identified using this software option. The penetration sites were numerous and well dispersed. The largest openings (lumen, pits and cracks) were responsible for most of the resin lost by over-penetration. The presence of resin in the cell walls (detected with the CLSM) proves their porosity without giving much information about the resin concentration. Finally, the atomic force microscope (AFM) enabled to recreate the finest surface details for these fibers samples. It was found that the fibrils aggregates orientation and size can influence the resin penetration and distribution. It was concluded that the porous structure of wood fibers and their affinity to water enable the resin to penetrate through capillary force. This phenomenon is stimulated by the high pressure, saturated steam, turbulent flow and heat. When injected in the pilot plant blowline, UMF resin was uniformly distributed over the fiber surface (22.5% coverage). The resin penetration was however important and also occurred in nanometric defaults of the wood fibers. Thus, industrial panels made out of very porous, damaged or small fibers will need more resin to fill the gaps in order to make a strong board.