Lithium Phosphonate Functionalized Polymer Coating for High-Energy Li[Ni0.8Co0.1Mn0.1]O2 with Superior Performance at Ambient and Elevated Temperatures

High-energy Ni-rich lithium transition metal oxides such as Li[Ni_0.8Co_0.1Mn_0.1]O₂ (NCM₈₁₁) are appealing positive electrode materials for next-generation lithium batteries. However, the high sensitivity toward moist air during storage and the high reactivity with common organic electrolytes, especially at elevated temperatures, are hindering their commercial use. Herein, an effective strategy is reported to overcome these issues by coating the NCM₈₁₁ particles with a lithium phosphonate functionalized poly(aryl ether sulfone). The application of this coating allows for a substantial reduction of lithium-based surface impurities (e.g., LiOH, Li₂CO₃) and, generally, the suppression of detrimental side reactions upon both storage and cycling. As a result, the coated NCM₈₁₁-based cathodes reveal superior Coulombic efficiency and cycling stability at ambient and, particularly, at elevated temperatures up to 60 ° C (a temperature at which the non-coated NCM₈₁₁ electrodes rapidly fail) owing to the formation of a stable cathode electrolyte interphase with enhanced Li⁺ transport kinetics and the well-retained layered crystal structure. These results render the herein presented coating strategy generally applicable for high-performance lithium battery cathodes.     

新型雷达波吸收材料研究进展

综述了国内外新型雷达波吸收材料的研究进展 ,根据雷达波吸收材料的吸波机理 ,详细介绍了纳米吸波材料、宽频谱吸波材料、手性吸波材料、导电高分子吸波涂料、结构吸波材料、多晶纤维吸波涂料、电路模拟吸波材料及等离子体吸波材料的最新研究现状。     

颗粒包覆法制备BZT-CT复合陶瓷

采用预合成的方法,分别用得到的单斜类锆钙钛矿相Bi2(Zn1/3Ta2/3)2O7(β-BZT)和钙钛矿相CaTiO3(CT)的粉末作为正负温度系数组元,用sol-gel法制备的ZnO-B2O3-SiO2玻璃,包覆两组元颗粒以阻止其相互反应,从而制备复相零温度系数微波陶瓷。结果表明:预合成及颗粒包覆法可抑制两相固溶反应,有效降低复相陶瓷的烧结温度,调节温度系数。特别是900℃烧结的w(CT)为4%的样品,其εr约为47,αε为2.8×10–6℃–1。     

Investigation of pattern coating on mould roller in roller-reversal imprint process

In order to prepare large area micropatterns with certain profile (certain aspect ratio) on kinds of substrates, especially on flexible substrate, a novel roller-reversal imprint (RRI) process is proposed, which starts with pattern coating of an ink (mostly a liquefied electronics materials, such as a semiconductor polymer) on a mould roller and ends with transferring the ink already patterned on the roller to the substrate. One of the critical challenges in RRI process is ensuring ink pattern coating and full filling to the microcavities on mould roller, which is one of the preconditions to achieve the pattern transferred on substrate with precise profile. In this paper, an ink coating model is established to reveal the ink filling situations versus different profile of microcavities on mould roller. Simulations show that, in the coating process, as the contact angle of ink on mould increasing, three basic filling situations, i.e., full filling, partial filling, and non-filling, will occur. In order to demonstrate the requirement of full filling, critical contact angle for full filling is proposed to distinguish the full filling and partial filling, and it is deeply dependant on the cross-sectional parameters (such as linewidth and the aspect ratio) of microcavities on mould roller. The critical contact angle is the watershed between full filling and partial filling, so it can be used as a guideline to choose the appropriate match between the surface energy of ink and mould to achieve full filling in RRI process. Experiments prove that the ink filling model and its simulation results are basically right, the cross-sectional parameters of microcavities on mould play great important roles to the critical contact angle, and only when the actual contact angle is smaller than the corresponding critical value, full filling can be obtained.     

Adaptive Ionogel Paint from Room-Temperature Autonomous Polymerization of α-Thioctic Acid for Stretchable and Healable Electronics

Development of a universal stretchable ionic conductor coating on insulating substrates, irrespective of surface chemistry and substrate shapes, is of immense interest for compliant and integrative large-area electronics but has proved to be extremely challenging. Existing methods relying either on the concurrent deposition of polymerizing precursors or on divided formulation and painting processes both suffer from several limitations in terms of adhesion, dehydration, processability, and surface pre-treatment. Here an ionogel paint that is readily prepared from the concentration-induced autonomous ring-opening polymerization of a natural small molecule—α-thioctic acid (TA) at ambient conditions is reported. The presence of ionic liquid prevents polyTA from further depolymerization via forming COOH···OS hydrogen bonds, resulting in ultra-stretchable ionogels with widely tunable mechanical and conductive properties, self-healability, as well as tissue-like strain adaptability. Moreover, owing to its universal adhesion and adjustable rheology, the ionogel paint can be directly coated on diverse substrates with arbitrary shapes (including porous materials, 3D printed frames, and elastic threads) to render them ionic conductivity. Applications of the ionogel-coated substrates as skin-like highly sensitive and durable large-strain sensors are further demonstrated, suggesting the ionogel paint's great potential in the emerging soft and stretchable electronics.     

Bioinspired Supramolecular Slippery Organogels for Controlling Pathogen Spread by Respiratory Droplets

Surface-deposited pathogens are sources for the spread of infectious diseases. Protecting public facilities with a replaceable or recyclable antifouling coating is a promising approach to control pathogen transmission. However, most antifouling coatings are less effective in preventing pathogen-contained respiratory droplets because these tiny droplets are difficult to repel, and the deposited pathogens can remain viable from hours to days. Inspired by mucus, an antimicrobial supramolecular organogel for the control of microdroplet-mediated pathogen spread is developed. The developed organogel coating harvests a couple of unique features including localized molecular control-release, readily damage healing, and persistent fouling-release properties, which are preferential for antifouling coating. Microdroplets deposited on the organogel surfaces will be spontaneously wrapped with a thin liquid layer, and will therefore be disinfected rapidly due to a mechanism of spatially enhanced release of bactericidal molecules. Furthermore, the persistent fouling-release and damage-healing properties will significantly extend the life-span of the coating, making it promising for diverse applications.     

发射药喷涂涂覆中涂覆液溶剂比的选择

为了优化端面局部阻燃发射药(端面涂覆,且小孔保持通气状态)涂覆层制备的喷涂工艺中涂覆液溶剂比,采用醋酸丁酸纤维素(CAB)作钝感剂,CAB与吸收药片TG-1(皮罗棉和硝化甘油为主要组分)作溶质,乙醇-丙酮(V/V=1/1)为溶剂,按照不同溶剂比制备得到涂覆液,用此涂覆液采用喷涂的工艺制成了涂覆层薄膜和涂覆发射药,利用万能材料测试仪获得涂覆层薄膜的力学强度,并利用三维视频对涂覆层在拉伸前、后的表面结构进行了局部放大观察分析,对不同溶剂比的涂覆发射药进行了密闭爆发器试验。结果表明,涂覆层的力学强度、表面及断裂处形貌与溶剂比有明显联系,溶剂比主要影响了涂覆层材质的均匀性和致密性,是影响涂覆层力学强度的重要因素,从而对涂覆发射药的燃烧渐增性产生影响。当溶剂比为8∶1时,露孔率达到95%以上,同时获得的涂覆层表面最为光滑,其薄膜的拉伸强度最大,为49.75 MPa,断裂处最为整齐,涂覆发射药的燃气动态活度变化值达到0.0920 MPa~(-1)·s~(-1),为所有样品中的最大值。     

石蜡/Estane5703复合钝感包覆CL-20的研究

为降低六硝基六氮杂异伍兹烷(CL-20)的机械感度,采用水悬浮法,以钝感剂石蜡及高分子聚合物Estane5703为包覆原料包覆CL-20,制备了4种包覆颗粒。用X射线衍射仪(XRD)、扫描电镜(SEM)、差示扫描量热分析(DSC)、机械感度测试方法表征包覆前后CL-20的晶型、包覆状态、热分解温度、机械感度。结果表明,石蜡与Estane5703可完整包覆CL-20,且包覆后CL-20的ε晶型未发生改变。采用水悬浮法包覆CL-20,当石蜡/Estane5703含量为总体系质量的2%/2%时,CL-20的撞击感度由100%降低至40%,摩擦感度由100%降低至48%;放热峰温提高5.4℃。     

宽频段太赫兹辐射计高吸收率涂层的特性

为了对宽频段高吸收率太赫兹辐射计的特性进行表征,研究了吸收涂层材料的特性;对常见的吸波材料在太赫兹波段的吸收率进行仿真,探寻在太赫兹波段具有高吸收率的材料;将碳化硅与3M黑漆进行混合,以进一步提高涂层的吸收率,并通过仿真调整涂层内碳化硅颗粒的尺寸;根据仿真结果制备混合涂层,利用太赫兹时域光谱仪对混合涂层样品进行测量。结果表明:该混合涂层样品的光谱吸收率大于0.99,与仿真结果基本吻合。