Air-Stable Li2S Cathode for Quasi-Solid-State Anode-Free Batteries with High Volumetric Energy

Anode-free batteries can maximize the energy density but their development is hindered by a lack of Li-rich cathodes for compensating the irreversible Li loss. Li₂S cathode is particularly appealing to this desire due to 2.6–4.7 folds more Li content and 4.2–6.8 times higher capacity than conventional intercalation cathodes. But its practical application is hindered by poor stability against moisture attacking in the air. Herein, a facile expendable polymer sheathing strategy toward air-stable Li₂S cathodes with high capacities for developing high-performance quasi-solid-state anode-free batteries without risk of cell leakage is reported. Tight protection by dense polymer barrier dramatically prolongs the lifetime of Li₂S cathode by 2,000 times at least in the air. Such air-stable Li₂S cathode allows for high compatibility of anode-free battery production with commercial schemes. More attractively, the polymer protective layer can in situ transform to multifunctional gel polymer electrolyte for releasing ionic pathways and enhancing cell performance by inhibiting LiPS loss and smoothing Li plating. With air-stable Li₂S cathode, the quasi-solid-state anode-free cells are assembled in ambient environment to deliver superb volumetric energy density of 1093 Wh L⁻¹. This study may shed new light to push the commercialization of high-energy and reliable anode-free batteries forward.     

Spinel-layered integrate structured nanorods with both high capacity and superior high-rate capability as cathode material for lithium-ion batteries

Spinel phase LiMn2O4 was successfully embedded into monoclinic phase layeredstructured Li2MrnO3 nanorods,and these spinel-layered integrate structured nanorods showed both high capacities and superior high-rate capabilities as cathode material for lithium-ion batteries (LIBs).Pristine Li2MnO3 nanorods were synthesized by a simple rheological phase method using α-MnO2 nanowires as precursors.The spinel-layered integrate structured nanorods were fabricated by a facile partial reduction reaction using stearic acid as the reductant.Both structural characterizations and electrochemical properties of the integrate structured nanorods verified that LiMn2O4 nanodomains were embedded inside the pristine Li2MnO3 nanorods.When used as cathode materials for LIBs,the spinel-layered integrate structured Li2MnO3 nanorods (SL-Li2MnO3) showed much better performances than the pristine layered-structured Li2MnO3 nanorods (L-Li2MnO3).When charge-discharged at 20 mA·g-1 in a voltage window of 2.0-4.8 V,the SL-Li2MnO3 showed discharge capadties of 272.3 and 228.4 mAh.g-1 in the first and the 60th cycles,respectively,with capacity retention of 83.8％.The SL-Li2MnO3 also showed superior high-rate performances.When cycled at rates of 1 C,2 C,5 C,and 10 C (1 C =200 mA·g-1) for hundreds of cycles,the discharge capacities of the SL-Li2MnO3 reached 218.9,200.5,147.1,and 123.9 mAh·g-1,respectively.The superior performances of the SL-Li2MnO3 are ascribed to the spineMayered integrated structures.With large capacities and superior high-rate performances,these spinel-layered integrate structured materials are good candidates for cathodes of next-generation high-power LIBs.     

(K0.45Na0.55)0.98Li0.02Nb0.77Ta0.18Sb0.05O3-Co0.85Cu0.15Fe2O4复合陶瓷的磁电性能研究

以压电体(K0.45Na0.55)0.98Li0.02Nb0.77Ta0.18Sb0.05O3和压磁体Co0.85Cu0.15Fe2O4为原料,通过传统的固相反应法制备了(1-x)[(K0.45Na0.55)0.98Li0.02Nb0.77Ta0.18Sb0.05O3]-xCo0.85Cu0.15Fe2O4多铁性复合陶瓷,并使用X射线衍射仪、扫描电子显微镜、压电测试仪、铁电测试仪和磁电耦合测试仪对物相、显微结构、压电、铁电、磁电耦合性能进行了分析。结果表明,复合陶瓷的相结构保持为(K0.45Na0.55)0.98Li0.02Nb0.77Ta0.18Sb0.05O3和Co0.85Cu0.15Fe2O4两种物相,但两者之间发生了轻微的化学反应。随着Co0.85Cu0.15Fe2O4压磁相含量的增加,复合陶瓷的压电系数从56pC/N减小到21pC/N,剩余极化强度略有降低。在压磁相含量为0.2时可获得4.3mV·cm-1·Oe-1的最佳磁电耦合系数。     

李白文化在现代创意产品中的设计再生

目的从文化创意产业的视角下研究如何从交叉学科的角度去审视李白文化,并应用于现代创意产品设计。方法借助跨学科的交叉研究方法,提炼出李白文化中的创意设计点。结论当代社会应从跨学科的角度研究李白文化,并实现设计再生,再生手法包括实体功能化、诗文图形化、图像娱乐化、虚拟数字化、意境造型化、设计绘画化等方面。     

In Situ Chelating Synthesis of Hierarchical LiNi1/3Co1/3Mn1/3O2 Polyhedron Assemblies with Ultralong Cycle Life for Li‐Ion Batteries

Layered lithium transition‐metal oxides, with large capacity and high discharge platform, are promising cathode materials for Li‐ion batteries. However, their high‐rate cycling stability still remains a large challenge. Herein, hierarchical LiNi_1/3Co_1/3Mn_1/3O₂ polyhedron assemblies are obtained through in situ chelation of transition metal ions (Ni²⁺, Co²⁺, and Mn²⁺) with amide groups uniformly distributed along the backbone of modified polyacrylonitrile chains to achieve intimate mixing at the atomic level. The assemblies exhibit outstanding electrochemical performances: superior rate capability, high volumetric energy density, and especially ultralong high‐rate cyclability, due to the superiority of unique hierarchical structures. The polyhedrons with exposed active crystal facets provide more channels for Li⁺ diffusion, and meso/macropores serve as access shortcuts for fast migration of electrolytes, Li⁺ and electrons. The strategy proposed in this work can be extended to fabricate other mixed transition metal‐based materials for advanced batteries.     

Fabricating Ir/C Nanofiber Networks as Free‐Standing Air Cathodes for Rechargeable Li‐CO2 Batteries

Li‐CO₂ batteries are promising energy storage systems by utilizing CO₂ at the same time, though there are still some critical barriers before its practical applications such as high charging overpotential and poor cycling stability. In this work, iridium/carbon nanofibers (Ir/CNFs) are prepared via electrospinning and subsequent heat treatment, and are used as cathode catalysts for rechargeable Li‐CO₂ batteries. Benefitting from the unique porous network structure and the high activity of ultrasmall Ir nanoparticles, Ir/CNFs exhibit excellent CO₂ reduction and evolution activities. The Li‐CO₂ batteries present extremely large discharge capacity, high coulombic efficiency, and long cycling life. Moreover, free‐standing Ir/CNF films are used directly as air cathodes to assemble Li‐CO₂ batteries, which show high energy density and ultralong operation time, demonstrating great potential for practical applications.     

喷雾干燥法制备富锂正极材料及其电化学性能

用喷雾干燥法制备Li_1.2Mn_0.54Ni_0.13Co_0.13O₂富锂正极材料并表征其结构、形貌以及电化学性能,研究了烧结温度对材料电化学性能的影响。结果表明：这种正极材料具有良好的层状结构,一次颗粒粒径为100 nm左右且分布均匀,样品的首次放电比容量为220.2 mAh/g,库伦效率为72.5%,18个循环后容量保持率为96.8%。电化学阻抗和循环伏安特性的测试结果表明,这种正极材料具有良好的电化学性能。     

Influence of Heat Input on Microstructure and Mechanical Properties of Laser Welding GH4169 Bolt Assembly—Numerical and Experimental Analysis

By conducting the numerical and experimental analysis, the influence of heat input on the microstructures and mechanical properties of laser welding GH4169 bolt assembly is systematically investigated. The weld formation, temperature field, and residual stress distribution during laser welding by using the finite element modeling are consistent with experimental results. The numerical simulation results show that the increase of heat input imparts lower residual stresses and higher temperature gradient. During the process of laser welding, the steepest temperature gradient and the peak residual stress arise in the fusion zone (FZ). In addition, the dissolution of γ″ and γ′ toward the fusion line increases in heat affected zone (HAZ), but only Laves phase is observed in FZ. With increasing heat input from 24 to 48 J mm⁻¹, the ultimate tensile strength of welded joints decreases. Both the lowest microhardness values and tensile failure of GH4169 alloy laser welded joint are in FZ. Herein, it is that the relationship among the heat input, microstructures, and mechanical properties of GH4196 bolt assembly in laser welding is systematically established, which will be of guiding significance for the selection of welding parameters in aerospace.     

李瑞环和合思想述论

在总结实践经验的基础上,李瑞环出版了一系列著作,其中,和合思想是这些著作中的基本理念和核心价值观之一。其作者对和合思想的论述,构成了一个科学的价值体系。李瑞环的和合思想源于对历史的反思,源于对传统文化现代价值的重新发掘,源于对当代社会问题的深入思考,源于对马克思主义哲学的正确理解。这一体系为建设社会主义和谐社会提供了重要的思想资源。