新型三元锂离子正极材料Li_2Ru_(1/3)Co_(1/3)M_(1/3)O_3的合成及其电化学性能

利用高温固相反应法制备了新型三元锂离子电池正极材料Li2Ru1/3Co1/3M1/3O3(M=Mn、Ni、Fe)。通过X射线衍射技术和电化学性能测试对Li2Ru1/3Co1/3M1/3O3的微观结构及其电化学性能进行了表征。研究结果表明,Li2Ru1/3Co1/3Ni1/3O3和Li2Ru1/3Co1/3Fe1/3O3为六方层状结构,空间群为R-3M,而Li2Ru1/3Co1/3Mn1/3O3保持了单斜结构;电化学性能测试表明Li2Ru1/3Co1/3Mn1/3O3的电化学性能优于掺杂Fe和Ni的三元材料,该材料具有良好的循环性能,在电流密度为16 m A/g情况下,首次充电容量达到190 m Ah/g,首次放电容量为171 m Ah/g,50次循环后容量保持率为98%。     

锂锰复合物在3V二次锂电池中的应用研究

利用固相反应法由热处理过的电解二氧化锰与LiOH·H2O的混合物制备锂锰复合物(CDMO),采用热分析研究了温度对γ-β-MnO2与LiOH·H2O混合物发生固相反应的影响,采用X射线衍射对二氧化锰和CDMO的晶体结构进行了表征,并将CDMO制成正极组装电池对其进行了恒电流充放电性能测试.研究结果表明,用该方法制备的CDMO有较好的充放电循环性能.     

Development of permanent magnet MnAlC/polymer composites and flexible filament for bonding and 3D-printing technologies

Searching for high-performance permanent magnets components with no limitation in shape and dimensions is highly desired to overcome the present design and manufacturing restrictions, which affect the efficiency of the final devices in energy, automotive and aerospace sectors. Advanced 3D-printing of composite materials and related technologies is an incipient route to achieve functional structures avoiding the limitations of traditional manufacturing. Gas-atomized MnAlC particles combined with polymer have been used in this work for fabricating scalable rare earth-free permanent magnet composites and extruded flexible filaments with continuous length exceeding 10 m. Solution casting has been used to synthesize homogeneous composites with tuned particles content, made of a polyethylene (PE) matrix embedding quasi-spherical particles of the ferromagnetic τ-MnAlC phase. A maximum filling factor of 86.5 and 72.3% has been obtained for the composite and the filament after extrusion, respectively. The magnetic measurements reveal no deterioration of the properties of the MnAlC particles after the composite synthesis and filament extrusion. The produced MnAlC/PE materials will serve as precursors for an efficient and scalable design and fabrication of end-products by different processing techniques (polymerized cold-compacted magnets and 3D-printing, respectively) in view of technological applications (from micro electromechanical systems to energy and transport applications).     

Interactions are important: Linking multi-physics mechanisms to the performance and degradation of solid-state batteries

The behaviour of solid-state batteries to many application-relevant operating conditions is intrinsically multiphysical and multiscale, involving the electrochemical performance and chemical stability coupled with the thermal and mechanical properties of multiple components. This review presents a holistic approach to discussing the multiscale physical-electro-chemical interactions and degradation mechanisms in solid-state batteries. While the propagation of lithium filaments depends strongly on the critical current densities, we show that effective prevention of excessive Li plating and stripping requires a combined understanding of solid-state electrochemistry, microstructure, mechanics, operating conditions, and their interactions. A review of how multiphysical interactions affect the optimum design of thin-film, three-dimensional and composite solid-state cell architectures is also included. Although the use of lithium metal as negative electrodes could improve the energy densities of solid-state batteries, we show that its high homologous temperature could cause cell failure during manufacturing. By comparing published model predictions with experimental observations, we present a critical analysis of the strengths and limitations of state-of-the-art models and characterisation techniques in solid-state battery research. This comprehensive mechanistic analysis provides an insight into the interplay among the multiple complex multiphysical mechanisms, shedding light on the process of cell design for next-generation solid-state batteries.     

Recent developments in garnet based solid state electrolytes for thin film batteries

This paper reviews the current status of, and new progress in, the field of solid state electrolytes (SSE) for lithium ion batteries. In addition to a review of current technologies, we are also presenting our novel results on pulsed laser processing of garnet based SSEs, specifically Li₇La₃Zr₂O₁₂ (LLZO). LLZO powders with a tetragonal structure were prepared by a sol–gel technique, then a pulsed laser annealing process was employed to covert the powders to cubic LLZO without any loss of lithium. The tetragonal LLZO exhibited a Li ion conductivity of 1.8 × 10⁻⁷ S/cm, whereas the laser annealed cubic LLZO showed a Li ion conductivity of 1.0×10⁻⁴ S/cm at room temperature. A systematic study of the effect of pulsed laser annealing (PLA) on the crystal structure, morphology, composition, and ionic conductivity of LLZO was performed via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and electrochemical impedance spectroscopy (EIS) measurements. These results demonstrate that PLA is a powerful processing technique for synthesizing the high ionic conductivity cubic phase of LLZO at relatively low temperatures, as compared to conventional methods.     

锂离子电池正极材料Li1+xV3O8合成及电化学性能的研究

利用液相沉淀法合成得到超细、粒径分布窄的球形V2O5,以该V2O5和LiOH*H2O为原料在较低温度下煅烧得到棒状Li1+xV3O8颗粒.采用XRD、SEM对样品的结构和形貌分别进行了表征.并在电压为1.8～3.8V范围,放电倍率为0.2C对制备的电极材料进行了电池性能测量.结果表明,采用比传统固相法低的温度和时间可以获得单斜晶系的纯相Li1+xV3O8.450℃合成的Li1+xV3O8首次放电比容量达到275mAh/g,550℃合成的Li1+xV3O8在循环15次后的比容量保持率为85%.     

A review of concepts and contributions in lithium metal anode development

Using lithium (Li) directly as metal anode for a higher energy density battery is one of the most attractive battery researches in the past decade. To address its intrinsic issues including uncontrolled growth of Li dendrites and unstable solid electrolyte interphase (SEI), which are believed as the main origins of safety issues and short lifetime, proposing the groundbreaking concepts and contributing valuable improvements in the development of Li metal anodes (LMAs) have always been the mandate of all battery scientists. This review presents a historical framework of various concepts and contributions in enabling LMAs to be applied practically. We begin with an overview of these important concepts and breakthroughs in different aspects to advance LMAs. Moreover, assisted by the big data sources from Web of Science, the major contributions from institutions, journals, corresponding authors, and highly cited papers are discussed and summarized. Finally, future trends and challenges are concluded for designing an ideal LMA. We hope that such as a comprehensive evolutionary story of LMAs can motivate more researchers to pave the way for high-energy lithium metal batteries (LMBs) in the future.     

液相制备石墨烯/硫复合材料及其在锂硫电池正极中的应用

采用氧化石墨烯(grapheneoxide,GO)作为制备石墨烯的前驱体,通过液相还原自组装过程与硫纳米颗粒进行复合,获得了高性能的还原氧化石墨烯/硫(r GO/S)复合正极材料。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)、拉曼光谱、X射线光电子能谱分析(XPS)等对材料微观形貌与结构进行表征。结果表明:硫纳米颗粒均匀分布在石墨烯片层间,并且硫纳米颗粒被石墨烯片层有效地封装,硫在35-r GO/S复合物中的质量分数高达83.6%。该35-r GO/S复合正极在0.2C电流密度下初始放电容量可达1197.3mAh·g^-1,经过200次循环后容量仍保持在730mAh·g^-1左右,表现出优异的循环性能。     

One-step fabrication of two-dimensional hierarchical Mn2O3@graphene composite as high-performance anode materials for lithium ion batteries

Two-dimensional (2D) hierarchical Mn2O3@graphene composite is synthesized by a one-step solid-phase reaction.The nanosheets of Mn2O3 are vertically grown on few-layered graphene,constructing a unique 2D hierarchical structure.As an anode material for lithium-ion batteries (LIBs),this hierarchical composite displays excellent electrochemical performances,showing an extraordinary reversible discharge capacity of 2125.9 mA h g-1.Moreover,a record high reversible capacity of 1746.8 mA h g-1 is maintained after 100 cycles at a current density of 100 mA g-1,which retains 82.2 ％ of the initial capacity.Such an outstanding performance could be attributed to its novel structure and the synergistic effects between the Mn2O3 and graphene.     

Li2ZrO3包覆锂离子电池正极材料Li[Li0.2Ni0.2Mn0.6]O2的制备及其电化学性能

富锂锰基材料因其具有较高的充放电比容量而备受关注。针对其首次库仑效率低、循环和倍率性能差的问题,将具有三维Li^+通道的锂离子导体Li2ZrO3引入至富锂锰基正极材料Li[Li0.2Ni0.2Mn0.6]O2的表面对其进行包覆改性研究。通过XRD,TEM,SEM,EDS综合分析可知:Li2ZrO3成功包覆到样品表面。包覆层厚度为3 nm(包覆量1%,质量分数)时复合材料的电化学性能得到显著提升。0.1 C(1 C=200 mAh·g^-1)倍率下首次放电比容量可达271.5 mAh·g^-1,库仑效率为72.4%,降低了首次不可逆容量损失;0.5 C下循环100周次后放电比容量为191.5 mAh·g^-1,容量保持率为89.5%,5 C倍率放电比容量为75 mAh·g^-1,倍率性能提升。适当厚度的均匀Li2ZrO3包覆层可在样品表面形成核壳结构使样品更稳定,减少表面副反应,阻止生成较厚SEI膜,这得益于Li2ZrO3本身的高电导率、高电化学稳定性和较好的锂离子传导性。     

PAA类黏结剂在锂电池中电化学性能研究进展

黏结剂是维持极片完整性必不可少的部分,对电池比容量、循环稳定等性能的提高非常重要。聚丙烯酸(PAA)因含有较多极性官能团,可溶于水,而被用作锂电池正负极黏结剂。PAA黏附性好,但极性基团使得分子链间形成的氢键导致PAA链刚性较大,不利于维持充放电过程中极片的完整性,因此,控制PAA官能团数量、改变官能团种类及PAA分子链结构,对锂电池电性能的提高势在必行。本文综述了近几年锂电池用PAA黏结剂的研究进展,重点介绍了PAA黏结剂的结构特性、改性及应用方式及其对不同种锂电池首次库伦效率、循环稳定性和阻抗性能的影响,并对PAA黏结剂的未来改性研究热点做了展望,探索PAA引入不同结构的弹性或导电聚合物后,对于黏结剂本身性能的影响,改善界面性能,以适用于不同活性材料正负极,提高锂离子传输速率,更好地提高锂电池的使用性能。     

Catalytic effect in Li-S batteries: From band theory to practical application

Lithium-sulfur (Li-S) batteries with high energy density have been considered one kind of promising next-generation energy storage system. However, the shuttling effect of polysulfides caused by the intrinsic sluggish reaction kinetics severely hinders their commercialization. The catalytic effect, a powerful solution towards polysulfides shuttling by accelerating the conversion of polysulfides, has aroused great attention. Numerous catalysts have been developed and proved to have catalytic effects in the past years. More importantly, many advanced in-situ characterization technologies and electronic structure analyses have been combined to study the “black box” of the catalytic process, which promotes the practical application of Li-S batteries entering a new stage. In this review, instead of summarizing recent achievements in catalyst materials and structural designs, the key issues that how to observe, understand, design, and use catalytic effect in Li-S batteries are systematically discussed. In-situ techniques are summarized to see the actual catalytic process. Band theory is applied to understand the electronic structure, thus deciphering design principles and strategies of catalytic effect. Subsequently, how to use the catalytic effect to realize Ah-level Li-S pouch cells is analyzed. Last, we propose a research paradigm for catalytic effect, which will enlighten the future development of Li-S batteries and other next-generation batteries based on conversion reactions.     

锂离子电池用多孔电极结构设计及制备技术进展

随着人们对锂离子电池需求的日益增加, 高能量密度和高功率密度锂离子电池技术成为研究热点之一。材料改性及新材料开发能有效提高电池的能量密度, 除此以外, 孔隙率、孔径大小与分布、曲折度及电极组分分布等电极的微观结构参数也是决定电极及电池性能的关键因素。通过优化电极结构设计提升高比能电池的性能逐渐成为人们关注的焦点。本文综述了锂离子电池多孔电极结构设计优化的研究进展, 总结了多孔电极结构设计要素及制备方法, 最后对电极结构设计优化以及推动新型制备技术的规模化应用在高比能锂离子电池领域的未来发展前景进行展望。     

NiaSi2O5（OH）4 Multi-Walled Nanotubes with Tunable Magnetic Properties and Their Application as Anode Materials for Lithium Batteries

Highly crystalline and thermally stable pure multi-walled Ni₃Si₂O₅(OH)₄ nanotubes with a layered structure have been synthesized in water at a relatively low temperature of 200–210 °C using a facile and simple method. The nickel ions between the layers could be reduced in situ to form size-tunable Ni nanocrystals, which endowed these nanotubes with tunable magnetic properties. Additionally, when used as the anode material in a lithium ion battery, the layered structure of the Ni₃Si₂O₅(OH)₄ nanotubes provided favorable transport kinetics for lithium ions and the discharge capacity reached 226.7 mA·h·g⁻¹ after 21 cycles at a rate of 20 mA·g⁻¹. Furthermore, after the nanotubes were calcined (600 °C, 4 h) or reduced (180 °C, 10 h), the corresponding discharge capacities increased to 277.2 mA·h·g⁻¹ and 308.5 mA·h·g⁻¹, respectively.      

From liquid to solid bonding in cohesive granular media

We study the transition of a granular packing from liquid to solid bonding in the course of drying. The particles are initially wetted by a liquid brine and the cohesion of the packing is ensured by capillary forces, but the crystallization of the solute transforms the liquid bonds into partially cemented bonds. This transition is evidenced experimentally by measuring the compressive strength of the samples at regular intervals of times. Our experimental data reveal three regimes: (1) Up to a critical degree of saturation, no solid bonds are formed and the cohesion remains practically constant; (2) The onset of cementation occurs at the surface and a front spreads towards the center of the sample with a nonlinear increase of the cohesion; (3) All bonds are partially cemented when the cementation front reaches the center of the sample, but the cohesion increases rapidly due to the strengthening of cemented bonds. We introduce a model based on a parametric cohesion law at the bonds and a bond crystallization parameter. This model predicts correctly the phase transition and the relation between microscopic and macroscopic cohesion.     

锂离子电池正极材料LiMnBO3的研究现状

简要概括了硼酸盐类正极材料LiMBO3的国内外研究现状。对LiMnBO3的结构、性能、改性及合成方法以及LiMnBO3在上述各方面存在的不足进行了归纳总结。     

Spatiotemporal mapping of microscopic strains and defects to reveal Li-dendrite-induced failure in all-solid-state batteries

Solid-state electrolytes (SSEs) are key to the success and reliability of all-solid-state lithium batteries, potentially enabling improvements in terms of safety and energy density over state-of-the-art lithium-ion batteries. However, there are several critical challenges to their implementation, including the interfacial instability stemming from the dynamic interaction of as-formed dendritic lithium during cycling. For this work, we emphasize the importance of studying the spatial distribution and temporal evolution of strains and defects in crystalline solid-state electrolytes at the micro-scale, and how this affects dendrite growth. A proof-of-principle study is demonstrated using the synchrotron radiation based micro Laue X-ray diffraction method, and a custom-developed in-situ cycling device. Defects and residual strains are mapped, and the evolution of intragranular misorientation is observed. The feasibility of using this technique is discussed, and recommendations for micro-strain engineering to address the Li/SSEs interfacial issues are given. Also, work directions are pointed out with the consideration of combining multi-techniques for “poly-therapy”.     

全固态锂离子电池中金属锂负极界面优化改性研究

以共聚物PEDOT-co-PEG作为锂金属阳极的表面改性层,采用磷酸铁锂复合阳极和“石榴石型”物质以及聚合氧乙烷聚合物组成的固体电解质制备了全固态锂离子电池。采用SEM分析了锂金属充电-放电反复操作后的形态学改变;采用电化学组抗谱试验研究了改性后的锂金属以及复合固体电解质接触面的稳定性并对全固态锂离子电池的充电-放电性能和界面稳定性进行了研究。结果表明,未改性的锂金属在固态电池充电-放电过程中会生成锂枝晶,从而导致全固态锂离子电池的高电流密度容量快速衰变;“石榴石型”物质以及聚合氧乙烷聚合物组成的固体电解质与改性后的金属锂具有良好的接触面,从而扼制锂枝晶的形成,提高全固态锂离子电池的机械性能;在PEDOT-co-PEG共聚物改性锂金属后,全固态锂离子电池的平稳性显著提高,且容量减弱放缓。