Constructing the high-areal-capacity,solid-state Li polymer battery via the multiscale ion transport pathway design

The parasitic Li dendrite formation and retarded ion diffusion dynamics inhibit the deployment of solid-state batteries (SSBs) at high areal capacity loadings. Here, we present the modular design of the Li⁺ percolating network by grafting the ionic-conductive polyether amine (PEA) at the multiple scales: the PEA modified zinc hydroxystannate (PEA@ZHS) (flame retardant units) and polyamide 6 (mechanical rigid units) are coherently introduced to optimize the PEO-based solid electrolyte (PX-PEA@ZHS) with the Young's modulus (3.41 GPa), ionic conductivity (4.29 × 10⁻⁴ S cm⁻¹ at 55 °C) and flame retardancy (22% reduction of heat release rate); on the other hand, PEA molecules are grafted onto the acetylene black additive to establish the dual conductive network, endowing two orders of magnitude increase of ionic conductivity for the high-compaction cathodes. The as-integrated symmetric cell exhibits a critical current density up to 0.8 mA cm⁻² and cycling endurance for 1000 h at 0.2 mA cm⁻²; upon the SSBs assembly with the record high loading of LiFePO₄ (12.4 mg cm⁻²), the high-areal-capacity, cycling stability as well as the extreme temperature endurance till 110 °C are simultaneously realized, which inspire the rational design of commercially feasible, energy-dense, flame-resistance energy storage prototype.     

电流模式和焊接方向对316L不锈钢增材制造成形的影响研究

目的 研究电流模式和焊接方向对316L不锈钢增材制造成形、内部微观组织和硬度的影响。方法 保持其他焊接工艺参数不变，采用Pulse、SpeedPulse、SpeedPulseXT这3种电流模式及同向和往复2种焊接方向进行单道多层堆积，采用光学显微镜观察增材制造件的微观组织并用洛氏硬度计测量其硬度值。结果 采用不同电流模式和不同焊接方向会影响增材制造件的冷却速率和凝固方式，进而影响增材制造件的表面成形和力学性能。同方向焊接时，随着电流模式的改变，焊接热输入增大，液态金属的流动性和铺展行为逐渐增强，增材制造件的高度尺寸减小，宽度尺寸增大，熔合线处δ铁素体受冷却速率的影响由块状变为蠕虫状，Pulse模式存在元素偏析;往复方向焊接时，外形尺寸没有明显的变化，熔合线处δ铁素体以胞状和蠕虫状为主。硬度测试结果表明，SpeedPulse模式硬度变化最小，SpeedPulseXT模式次之，Pulse模式硬度变化最大。结论 采用MIG焊进行316L不锈钢增材制造时，不同电流模式会对增材件的成形、内部金相组织和硬度产生影响。采用同方向焊接比往复方向焊接对增材件形貌的影响更大。     

Analysis and proposition of limiting current density measurement protocol

Limiting current density at different temperatures, backpressures, and balance gases can be used to separate molecular diffusion resistance, Knudsen diffusion resistance and local transport resistance of membrane electrode assembly (MEA). However, the measurement of limiting current density has no unified protocol. The diverse choices in the literature, either in the control of current or voltage or in the atmosphere like relative humidity and O₂ concentrations, make it difficult to compare the results and identify the true bottleneck hindering the mass transport. In this work, the current-voltage curves obtained by current scanning/stepping and voltage scanning/stepping methods under dilute O₂ of different concentrations and a wide range of relative humidity were measured and analyzed systematically. It is found that the voltage stepping method is superior to the other three ways of control for the reliable determination of the limiting current density. Aided with simultaneous electrochemical impedance spectroscopy measurement, the limiting current density can be determined with pinpoint accuracy. When the limiting current density is just used to qualitatively evaluate different MEA, the voltage scanning method can be used instead for its high time efficiency. The selection of the atmosphere also plays an important role in suppressing the distortion from excessive water and reducing the spurious contribution from proton conduction resistance. It is found that O₂ concentrations at 0.5 vol% and relative humidity at 90% can give the best estimation of O₂ transport resistance in membrane electrode assembly.     

Suppressed atomic diffusion in flash sintering of bismuth telluride

Bi₂Te₃ materials were synthesised by the recently developed flash sintering (FS) method, and the rapid densification effect was studied. Whereas a fully densified sample can be obtained with a feeding current of 1.2 kA for 1 s, the limited heating effect reduces grain growth and atomic diffusion. Interestingly, the significant chemical reaction suppression with oxygen contaminants, which induces electron doping, has a meaningful electronic properties impact. The large negative Seebeck coefficient of ? 138.9 μV/K in the sample prepared by conventional current sintering of 773 K for 3 min, in which the oxygen diffuses into the Bi₂Te₃ phase, is significantly reduced to ? 8.5 μV/K in the FS sample, much closer to the intrinsic p-type conduction in Bi₂Te₃ raw powder. These results suggest that the limited FS heating effect may contribute to preserving the intrinsic raw powder properties in the sintered material by avoiding excess atomic diffusion and undesirable reactions.     

Nickel hydroxide armour promoted CoP nanowires for alkaline hydrogen evolution at large current density

The development of hydrogen evolution activity (HER) electrocatalyst that can run durably and efficiently under the large current density is of special significance but still challengeable for the massive production of hydrogen. Herein, a CoP/Ni(OH)₂ nanowire catalysts grown on Co foam (CF) with a three-dimensional heterojunction structure has been successfully prepared by electrodepositing nickel hydroxide on the surface of cobalt phosphide. The prepared CoP/Ni(OH)₂–15 min sample reveals a superior HER activity and stability. It merely requires ultralow overpotentials of 108 and 175 mV to 100 and 500 mA cm^?2, respectively. In addition, the long-term stability test shows that the catalyst (CoP/Ni(OH)₂–15 min) can operate stably for at least 70 h at 400 mA cm^?2. Utilizing NiFe-LDH/IF with high OER activity, the NiFe-LDH/IF || CoP/Ni(OH)₂–15 min catalyst system possesses the same outstanding performance for overall water splitting (OWS), which can accomplish ≈ 500 mA cm^?2 at 1.74 V in 1 M KOH electrolyte. Moreover, the NiFe-LDH/IF || CoP/Ni(OH)₂–15 min couple can work for more than 80 h at 500 mA cm^?2, indicating its a great prospect in the area of electrolysis water. Such excellent catalytic performance is mainly attributed to the armor effect of Ni(OH)₂, which can not only promote the rapid decomposition of water molecules, but also prevent the loss of phosphorus and enhance the synergistic effect of CoP and Ni(OH)₂. This work can offer a significant reference for the design with high-performance and durable transition metal phosphide electrocatalysts.     

三级连续碳化法生产纳米碳酸钙新工艺研究

采用有效容积依次递增的预塔、中塔、后塔三个碳化塔串联,塔内气液连续逆流操作、塔间气液连续并流或错流操作,严格控制氢氧化钙浆液的浓度、流量、温度和碳化气的浓度、流量,并通过pH计或电导仪进行跟踪检测碳化度,可实现纳米碳酸钙生产工艺连续化、产品质量稳定化、产量规模化.     

湖北省大冶铁矿区内矿石磁性特征分析

从磁铁矿矿石的磁性差异入手,对铁(铜)矿床中各矿体的矿石磁性特征进行了系统的研究,得出大冶铁矿铁(铜)矿床是一个磁性特征变化较大的矿区,影响磁铁矿矿石磁性特征的主要因素为矿石的矿物组成、化学成分以及矿石的结构和构造。     

一种功能齐全的高可靠性雷管引爆执行电路设计

本章提出了一种针对工程爆破的功能齐全的高可靠性执行电路设计,该电路可执行"安全/充电"、"起爆"及"自毁"三种工作指令。系统采用电压逆变电路设计,提高了引爆负载的能力,保证了大电流的输出和点火需要;系统设置了"自毁"功能,可靠销毁未起爆的雷管,保障后继清理工作的绝对安全。设计合理,性能稳定,精确度高,实现了在有外界干扰的情况下能够无串控、无误动作。     

KGT可控硅调速在矿用蓄电池机车上的应用

介绍了直流电动机的调速原理,直流斩波器调压原理,KGT可控硅调速电路简介及工作原理。KGT应用在电机车上起动平稳,调速均匀,节约电能,延长蓄电池的使用寿命。