Lithiation MXene Derivative Skeletons for Wide-Temperature Lithium Metal Anodes

Lithium (Li) metal, as an appealing candidate for the next-generation of high-energy-density batteries, is plagued by its safety issue mainly caused by uncontrolled dendrite growth and infinite volume expansion. Developing new materials that can improve the performance of Li-metal anode is one of the urgent tasks. Herein, a new MXene derivative containing pure rutile TiO₂ and N-doped carbon prepared by heat-treating MXene under a mixing gas, exhibiting high chemical activity in molten Li, is reported. The lithiation MXene derivative with a hybrid of LiTiO₂-Li₃N-C and Li offers outstanding electrochemical properties. The symmetrical cell assembling lithiation MXene derivative hybrid anode exhibits an ultra-long cycle lifespan of 2000 h with an overpotential of ≈30 mV at 1 mA cm⁻², which overwhelms Li-based anodes reported so far. Additionally, long-term operations of 34, 350, and 500 h at 10 mA cm⁻² can be achieved in symmetrical cells at temperatures of −10, 25, and 50 °C, respectively. Both experimental tests and density functional theory calculations confirm that the LiTiO₂-Li₃N-C skeleton serves as a promising host for Li infusion by alleviating volume variation. Simultaneously, the superlithiophilic interphase of Li₃N guides Li deposition along the LiTiO₂-Li₃N-C skeleton to avoid dendrite growth.     

Laboratory study of property-modified prebaked carbon anode and application in large aluminum electrolysis cells

A kind of complex additive mainly containing Al, Mg, F, and O was prepared. The synthetical performances of the property-modified prebaked anodes containing additives were tested in laboratory. On the basis of ideal testing results obtained, a large number of industrial prebaked property-modified anodes are prepared in a large-scale aluminum company. Further more, they are all used in 160 kA prebaked anode aluminum electrolysis cells. The statistic result show that, compared with common anodes, the property-modified ones enhance current by 11.6 kg per ton aluminum averagely.     

Structural and surface properties of thermally prepared Ti/RhxTi(1−x)Oy electrodes: I—influence of preparation parameters

Electrodes of Rh_xTi_(1−x)O_y nominal composition were prepared by thermal decomposition of the chloride or nitrate precursor salts dissolved in strongly acidic medium and applied by brush to both sides of a Ti° support. A systematic study of the influence of calcination temperature and time as well as oxygen flux was conducted. The coatings were characterised by SEM, EDAX, XRD, open circuit potential measurements and cyclic voltammetry (CV). Visible-ultraviolet spectrophotometry was employed to identify the chemical form of the precursor in solution while thermogravimetric analysis (TGA) was used to assess the decomposition temperature ranges. Optimisation of the coating preparation parameters showed coatings obtained from [Rh(H₂O)₆](NO₃)₃ precursor dissolved in HNO₃ 1:2 (v/v) and fired at 430 °C for 2 h in a 5 l min⁻¹ oxygen stream-furnished stable electrodes having the highest electrochemically active surface area.     

MnS夹杂物诱发钢材点蚀综述

MnS夹杂物诱发钢材点蚀,对钢材服役寿命、工作生产安全和社会经济发展产生巨大危害。首先,分析了MnS夹杂物诱发钢材点蚀的机理,包括电偶腐蚀机理、S和Cl-协同作用机理、封闭区域加速点蚀机理、贫铬区机理和微缝隙机理;其次,汇总了MnS夹杂物大小、形貌、分布,Cl-浓度、温度和应力对MnS夹杂物诱发钢材点蚀的影响;然后,总结了钢材防腐蚀的常用措施;最后,展望了防止MnS夹杂物诱发钢材点蚀的未来研究方向。     

The properties of electroactive ruthenium oxide coatings supported by titanium-based ternary carbides

Electroactive oxide coatings on titanium, known in industrial chlorine production as dimensionally stable anodes (DSA), are of limited service life owing to the dissolution of active oxide, but also due to low corrosion stability of titanium, at high anodic potentials and elevated temperatures. In order to improve the anode stability, ternary carbide, Ti₃SiC₂, could be a promising material for the coating support, since chemical corrosion stability of Ti₃SiC₂ is significantly higher if compared to Ti. In this work, the possibility of the sol-gel preparation of RuO₂-TiO₂ coating on Ti₃SiC₂ is investigated and comparison of the basic characteristics of sol-gel processed oxide coating, Ru_0.5Ti_0.5O₂, applied onto Ti₃SiC₂ and Ti, is reported. Microscopic investigation of the coating surface showed that considerably less cracked coating is formed onto the Ti₃SiC₂ support. Slightly higher voltammetric currents are registered for Ti₃SiC₂-supported coating in H₂SO₄ and NaCl solution. The activity for chlorine evolution is higher, while the currents of oxygen evolution reaction are lower for Ru_0.5Ti_0.5O₂/Ti₃SiC₂ anode in comparison to Ru_0.5Ti_0.5O₂/Ti anode. Even though these preliminary results on the basic electrochemical properties of Ru_0.5Ti_0.5O₂/Ti₃SiC₂ anode and chemical stability of Ti₃SiC₂ are promising, the accelerated stability test in NaCl solution showed that coated Ti₃SiC₂ is not anodically stable and lasts considerably shorter than Ru_0.5Ti_0.5O₂/Ti anode prepared and tested under the same conditions.     

中性溶液中焊料-铜 电偶腐蚀缓蚀剂的研究

研究了在中性介质中,焊料-铜的接触腐蚀及苯骈三氮唑、液体硅酸钠的缓蚀效果。结果表明焊料-铜短接时,苯骈三氮唑、液体硅酸钠能明显减小阳极金属焊料的腐蚀。苯骈三氮唑、液体硅酸钠加入内燃机车冷却水添加剂配方中,抑制焊料电偶腐蚀。     

铜在雨水中的腐蚀行为电化学研究

采用电化学动电位扫描和交流阻抗研究了铜在模拟斯 德哥尔摩雨水中的腐蚀行为.铜表面存在少量腐蚀产物时，铜在雨水中的腐蚀主要由电化学 机制控制；随着腐蚀产物在铜表面的大量生成和沉积，存在腐蚀产物的区域和不存在腐蚀产 物的区域，形成了电偶腐蚀电池，腐蚀产物区为阴极.     

输气钢管内壁椭圆形坑失效原因分析

为分析某输气用X52QS钢级无缝钢管内壁椭圆形凹坑失效原因,通过力学性能测试、金相检测、化学成分分析、扫描电镜（SEM）、物相（XRD）分析等手段,对该凹坑产生原因进行综合分析。结果发现,凹坑区的C、Cr、Mo、Ti、B等元素含量高于正常区,且偏聚在凹坑区;C、B元素含量超标,化学成分不均导致凹坑区金相组织不均匀,使凹坑区发生微观原电池反应,凹坑区成为阳极被腐蚀而减薄;此外,凹坑内表面的CaCO3和SiO2含量较高,造成凹坑区垢下腐蚀;凹坑区表面膜疏松造成浓差电池,在介质冲刷等共同作用下会加速腐蚀,凹坑区壁厚持续减薄,最终形成更大的椭圆形凹坑。最后对样管最薄凹坑剩余厚度进行计算,发现已无法满足设计压力要求,建议换钢管或者降低设计压力后二次利用。     

微小电偶腐蚀电流的准确测定

为了更多地获得电偶腐蚀的信息并揭示其本质规律，提出了电偶腐蚀试验实时监测模型。通过选用不同设备对试样的电偶腐蚀微小电流的测量，结果发现：选用现成设备测量试样的电偶腐蚀微小电流时，测量电流波动非常大，噪声明显超过实际信号输入——电偶腐蚀电流。经自行开发研制的MCD01电偶腐蚀计可以准确的测量腐蚀电流，特别是微小电偶腐蚀电流。