氧化物夹杂对Al-Zn-In-Si牺牲阳极电化学性能的影响

以不同铁含量的Al-Zn-In-Si牺牲阳极为研究对象,考察了精炼前后阳极微观组织的变化.采用恒电流测试、动电位极化曲线、电化学阻抗等测试手段,对阳极的电化学性能进行了研究.结果表明：氧化物夹杂的存在使阳极的开路电位和工作电位正移,阳极的极化程度增大,同时还造成了阳极电流效率在一定程度上的损失.     

Fabrication of 3D Microfluidic Channels and In‐Channel Features Using 3D Printed,Water‐Soluble Sacrificial Mold

Recent advent of additive manufacturing potentiates the fabrication of microchannels, albeit with limitations in resolution of printed structures, freedom of geometry, and choice of printable materials. Herein, a method is developed by sacrificial molding to fabricate microchannels in various polymer matrices and geometries. This method allows for rapid fabrication of 3D microchannels and channels harboring intricate in‐channel features. The method uses commercially available fused deposition modeling 3D printer and filament made of polyvinyl alcohol (PVA). Mechanically stable molds are fabricated for 3D microchannels that can be completely removed in water. Importantly, the PVA mold is stable and resilient in hydrogels despite being hygroscopic. Perfusion channels are fabricated in biocompatible substrates such as gelatin and poly(ethylene glycol) diacrylate. Fabrication of the network of 3D multilayer microchannels is demonstrated by preassembling sacrificial molds from modular pieces of molds. Intricate staggered‐herringbones grooves (SHGs) are also fabricated within microchannels to produce micromixers. The versatility and resilience of the method developed here is advantageous for biological and chemical applications that require 3D configurations of microchannels in various matrices, which would not be compatible with fabrication by direct 3D printing and softlithography.     

Potassium‐Ion Battery Anode Materials Operating through the Alloying–Dealloying Reaction Mechanism

Anode materials that operate via the alloying–dealloying reaction mechanism are well known in established and maturing battery systems such as lithium‐ion and sodium‐ion batteries. Recently, a new type of metal‐ion battery that utilizes K⁺ ions in its operating principle has attracted significant attention due to a possibility of building high voltage cells using an abundant potassium ionic shuttle. Establishing promising electrode materials is of paramount importance for this new type of battery. This feature article summarizes available early results on the alloying–dealloying anode materials in potassium electrochemical cells. Based on original research (some data are presented for the first time) and independently published literature, experimental results on silicon, tin, phosphorus, antimony, and lead‐containing anodes are critically discussed. The electrochemical properties, charge storage mechanisms, and achievable capacities are considered. The results are compared with the behaviors of the same materials in lithium and sodium cells, and the importance of the volumetric parameters of electrodes is emphasized. Finally, a number of further research directions in these interesting anode materials are suggested. The feature article provides a useful reference for the growing number of researchers and specialists working in the field of emerging metal‐ion batteries with non‐lithium chemistries.     

Modification of petroleum coke by different additives and the impact on anode properties

Anodes, which provide the carbon required for aluminum production, are made from dry aggregates (petroleum coke, rejected anodes, and butts) with coal tar pitch as the binder. Good quality anodes require good interaction between coke and pitch, and this relies on good wetting properties. The objectives of this work are to analyze the wetting properties of four different cokes with and without modification using an additive and to test the effect of the modified coke on anode properties. A FTIR study was done to identify functional groups in non‐modified and modified coke samples since they play an important role on coke‐pitch interactions. The wetting tests were done using the sessile‐drop method to measure the contact angle between coke and pitch. The results showed that the additive improved the wettability of all four cokes by pitch. The least wettable coke was chosen to produce anodes. For anode production, the entire dry aggregate is modified. The additive was mixed with the dry aggregate using two different approaches (one day earlier and 5 min before mixing). The anodes were characterized before and after baking. The early treatment with the additive was found to be better for the modification of dry aggregate.

     

碳包覆锂锰钒氧纳米材料的制备及其电化学性能

以醋酸锂、醋酸锰、五氧化二钒、过氧化氢为原料,葡萄糖作碳源,采用溶胶-凝胶法结合水热合成技术制备了不同碳质量分数的碳包覆锂锰钒氧纳米材料LiMnVO_4/C。利用SEM、TEM、XRD、Raman、EDS、TG对其形貌和结构进行了表征。结果表明,所制备的纳米材料呈立方晶系结构,经碳包覆后的复合纳米材料的颗粒分散性较好。电化学测试结果表明,在相同的测试条件(充放电电压为0.01~3.00 V,充放电电流密度为100 m A/g)下,碳质量分数为0%、5%、10%和15%的碳包覆锂锰钒氧纳米材料的首次充电比容量分别为682、686、696和580 m A·h/g,60次循环后的充电比容量分别为226、336、513和440 m A·h/g。因此,碳质量分数为10%的碳包覆锂锰钒氧纳米材料具有较好的循环稳定性和较高的充电比容量。合适的碳包覆质量分数不仅能提高纳米电极材料的界面稳定性,抑制晶粒的长大和团聚,而且能改善复合电极材料的电子导电性。     

苯丙氨酸的电化学储锂性能

为了研究苯丙氨酸的电化学储锂活性,首先借助傅立叶红外光谱(FTIR)和扫描电镜(SEM)对苯丙氨酸的微观结构及形貌进行了表征,然后将其用作锂离子电池负极活性材料,并通过恒流充/放电、循环伏安(CV)和交流阻抗(AC)技术研究了其电化学脱/嵌锂性能.结果表明:苯丙氨酸负极材料在0.1C循环充/放电50次后,可逆放电比容量为55.2 mAh·g-1;同时表现了良好的倍率性能,表明有机苯丙氨酸作为锂离子电池负极活性材料的良好可行性.     

固体氧化物燃料电池阳极材料的抗积炭方法

传统的固体氧化物燃料电池(SOFC)阳极采用镍基金属陶瓷材料,在CH4等碳氢化合物为燃料的阳极反应中,会出现积炭。分析以碳氢化合物为燃料的SOFC阳极材料的积炭机理,阐述反应温度、水蒸汽等因素对阳极积炭的影响,介绍Ni基陶瓷阳极性能优化和解决积炭的方法,对SOFC其他阳极材料以及未来阳极材料的发展方向进行研究展望。     

亚硫酸铵还原浸出电解锰阳极泥中锰和硒的研究

研究了以亚硫酸铵为还原剂,在酸性条件下从电解锰阳极泥中浸出锰和硒的工艺。考察了浸出温度、硫酸浓度、亚硫酸铵用量及反应时间对锰和硒浸出率的影响。结果表明,在硫酸浓度1.69 mol/L、反应时间30 min、浸出温度30 ℃和还原剂用量为12.0 g的条件下,锰和硒的浸出率分别达到98.78%和93.94%。