Interlamellar Lithium-Ion Conductor Reformed Interface for High Performance Lithium Metal Anode

Lithium metal anodes are promising for application in new-type secondary batteries. Unfortunately, low cycle life and safety peril induced by uncontrollable dendrites growth and weak solid electrolyte interface (SEI) have blocked their utilization. In this work, an interlamellar lithium-ion conductor of lithium-montmorillonite (Li-MMT) is applied to enhance the SEI properties, inhibit dendrites-germination, and thus significantly enhance electrochemical performance. Such a well-designed Li-MMT SEI not only possesses inherent fast lithium-ion channels, but also works as a reservoir to supply adequate lithium-ions in the interlaminations and periphery of Li-MMT nanosheets, offering fast lithium-ion transfer in interlaminations and sheet-to-sheet. Furthermore, the strong trend of lithium-ion absorption of Li-MMT is confirmed by density functional theory calculations and stable lithium deposition under Li-MMT SEI layer at 10 mA cm⁻² is verified via finite element modeling. As a result, a steady lithium deposition process without dendrites is achieved. Coulombic efficiency of the half-cell accomplishes a mean value of 99.1% over 400 cycles at 1 mA cm⁻², while Li-LiFePO₄ full cells show a stable capacity up to 120 mAh g⁻¹ and steady circulation over 400 loops at 1C. This work offers a novel strategy to design a high-performance SEI layer and suppress dendrite growth.     

Nanoflake Arrays of Lithiophilic Metal Oxides for the Ultra‐Stable Anodes of Lithium‐Metal Batteries

A molten lithium infusion strategy has been proposed to prepare stable Li‐metal anodes to overcome the serious issues associated with dendrite formation and infinite volume change during cycling of lithium‐metal batteries. Stable host materials with superior wettability of molten Li are the prerequisite. Here, it is demonstrated that a series of strong oxidizing metal oxides, including MnO₂, Co₃O₄, and SnO₂, show superior lithiophilicity due to their high chemical reactivity with Li. Composite lithium‐metal anodes fabricated via melt infusion of lithium into graphene foams decorated by these metal oxide nanoflake arrays successfully control the formation and growth of Li dendrites and alleviate volume change during cycling. A resulting Li‐Mn/graphene composite anode demonstrates a super‐long and stable lifetime for repeated Li plating/stripping of 800 cycles at 1 mA cm^?2 without voltage fluctuation, which is eight times longer than the normal lifespan of a bare Li foil under the same conditions. Furthermore, excellent rate capability and cyclability are realized in full‐cell batteries with Li‐Mn/graphene composite anodes and LiCoO₂ cathodes. These results show a major advancement in developing a stable Li anode for lithium‐metal batteries.     

Hydrofluoric Acid-Removable Additive Optimizing Electrode Electrolyte Interphases with Li+ Conductive Moieties for 4.5 V Lithium Metal Batteries

High-voltage lithium metal batteries (LMBs) are capable to achieve the increasing energy density. However, their cycling life is seriously affected by unstable electrolyte/electrode interfaces and capacity instability at high voltage. Herein, a hydrofluoric acid (HF)-removable additive is proposed to optimize electrode electrolyte interphases for addressing the above issues. N, N-dimethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) aniline (DMPATMB) is used as the electrolyte additive to induce PF₆⁻ decomposition to form a dense and robust LiF-rich solid electrolyte interphase (SEI) for suppressing Li dendrite growth. Moreover, DMPATMB can help to form highly Li⁺ conductive Li₃N and LiBO₂, which can boost the Li⁺ transport across SEI and cathode electrolyte interphase (CEI). In addition, DMPATMB can scavenge traced HF in the electrolyte to protect both SEI and CEI from the corrosion. As expected, 4.5 V Li|| LiNi_0.6Co_0.2Mn_0.2O₂ batteries with such electrolyte deliver 145 mAh g⁻¹ after 140 cycles at 200 mA g⁻¹. This work provides a novel insight into high-voltage electrolyte additives for LMBs.     

Fluoroethylene Carbonate Additives to Render Uniform Li Deposits in Lithium Metal Batteries

Lithium (Li) metal has been considered as an important substitute for the graphite anode to further boost the energy density of Li‐ion batteries. However, Li dendrite growth during Li plating/stripping causes safety concern and poor lifespan of Li metal batteries (LMB). Herein, fluoroethylene carbonate (FEC) additives are used to form a LiF‐rich solid electrolyte interphase (SEI). The FEC‐induced SEI layer is compact and stable, and thus beneficial to obtain a uniform morphology of Li deposits. This uniform and dendrite‐free morphology renders a significantly improved Coulombic efficiency of 98% within 100 cycles in a Li | Cu half‐cell. When the FEC‐protected Li metal anode matches a high‐loading LiNi_0.5Co_0.2Mn_0.3O₂ (NMC) cathode (12 mg cm^?2), a high initial capacity of 154 mAh g^?1 (1.9 mAh cm^?2) at 180.0 mA g^?1 is obtained. This LMB with conversion‐type Li metal anode and intercalation‐type NMC cathode affords an emerging energy storage system to probe the energy chemistry of Li metal protection and demonstrates the material engineering of batteries with very high energy density.     

Dendrite‐Free Lithium Plating Induced by In Situ Transferring Protection Layer from Separator

Lithium (Li) metal anodes are regarded as a promising pathway to meet the rapidly growing requirements on high energy density cells, owing to their highest gravimetric capacity (3840 mAh g^?1) and their lowest redox potential. The application of Li metal anodes, however, is still hindered by undesired dendrites formation and endless consumption of liquid electrolyte due to a continuous reaction on interface of electrolyte/Li‐metal without a stable solid–electrolyte–interface (SEI) layer. A stable protection layer is formed on Li metal anode by in situ transferring the coating layer from polymer separator. The Li anode protection strategy is developed with an in situ formed protection layer transferred through the reduction of a coating layer on polymer separator. A PbZr_0.52Ti_0.48O₃ (PZT) coating layer on polypropylene (PP) separator is reduced by Li metal anode to produce a Pb metal containing composite layer, which could form Pb–Li alloy and adhere to the surface of Li metal anode after the reaction and improves the Li plating/stripping efficiency owing to the formation of a more homogenized electric field. Both the Li/Li symmetric cells and LiFePO₄/Li cells with this PZT precoated PP separators exhibit significantly improved Coulombic efficiency and cycling life.     

新型广谱金刚石破碎岩石工具的研制

新型广谱金刚石钻头由钻头钢体和金刚石刀头组成。金刚石刀头由若干含金刚石孕镶层和纯合金层相间组成。该新型金刚石钻头破碎岩石是以金刚石破碎为主、以破碎穴效应为辅的方式进行的。其特点是破碎岩石效率较高，对岩石的适应性较强，使用寿命高，钻头的导向性及工作稳定性较好，钻进效果与钻进质量明显提高。     

丝普纶系列服装面料的研制

介绍高科技低特丝普纶纤维的主要特点及其长丝与棉或涤棉交织面料的生产研制，根据生产实践认为，对丝普纶长丝加以网络处理是保证织造顺利进行的必要条件，同时对织造中出现的断纬等问题提出了有效可行的解决措施。     

矿用钢丝绳断丝信号处理技术

针对目前国内各种钢丝绳断丝检测仪的缺陷 ,提出了应用小波变换和神经网络技术对检测信号进行分析处理 ,以提高仪器的精度和灵敏度 ,并详述了用小波分析法提取信号的特征量以及用BP网络建立断丝识别模型的方法。     

瞬变电磁法在断层防治水中的应用

该文讨论了瞬变电磁法的原理,介绍了瞬变电磁法在阳城煤矿开拓大巷过季庄断层的应用设计施工,给出了季庄断层瞬变电磁法探测结果及结论,并根据结论采取了过断层的有效措施,通过巷道施工过程中的超前钻探及巷道实际揭露的断层的情况,验证了瞬变电磁法在断层防治水应用中可靠有效性。     

Spherulitic Growth of Apatite in a MgO─CaO─SiO2─P2O5 Glass

Differential thermal analysis, X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis, and transmission electron microscopy were used to study the crystallization of a glass with a composition of 11.2 wt% MgO, 40.5 wt% CaO, 33.3 wt% SiO₂, and 15 wt% P₂O₅. A two-phase "composite," which was composed of apatite and an intermediate phase (H-phase), was formed under appropriate heat-treatment conditions. The spherulitic morphology of apatite phase transformed from "open sheaf" into ellipsoidal as samples were heated to a higher temperature. These phenomena were due to the intermediate H-phase becoming unstable at this temperature so that the retardation effect on the apatite dendritic growth disappeared.