锰的氧化物在锂离子二次电池中的应用

锰的氧化物由于资源丰富,价格便宜、无毒无污染等特点,在锂离子二次电池正极材料的大规模生产中广具前景。简述了各种锰氧化物的制备方法,晶体结构及其与电化学性能的关系。     

Molten salts for rechargeable batteries

The growing demand of advanced electrochemical energy storage devices for various applications, including portable electronic products, electric vehicles, and large-scale energy storage grids, has triggered extensive research interests and efforts on various rechargeable batteries such as lithium/sodium-ion batteries (LIBs/NIBs), aluminium-ion batteries (AIBs), liquid metal batteries (LMBs), and molten-air batteries (MABs) in the past decades. A key issue to push forward the development of these batteries is the exploration of high-performance electrodes and electrolytes, which calls for efficient and versatile synthetic methods. Molten salts (MSs), liquid-phase ionic compounds or mixtures, provide an effective platform to widen the reaction temperatures and enrich the chemical environments for the synthesis of novel electrode materials and electrolytes. In this review, the general principles of molten salts and recent research progresses on molten salt-based battery materials are surveyed. Molten-salt synthesis of electrode materials, including sintering and electrolysis, are emerging as competitive substitutes for conventional synthesis techniques. These methods have shown their effectiveness and uniqueness in adjusting the crystal structure, morphology, and performance of electrode materials for LIBs/NIBs, as suggested by recent progresses and applications of diverse cathodes (layered oxides, spinel oxides, polyanions, etc.) and anodes (metal oxides, alloys, carbons, etc.). Furthermore, the applications of molten salts as effective electrolytes are demonstrated in representative new-type secondary batteries including AIBs, LMBs and MABs. Finally, the emerging opportunities, challenges, and interesting research trends are envisioned to promote the further development of molten-salt methodology for rechargeable batteries.     

氧化钒作锂离子电池正极材料的研究进展

V_2O_5具有独特的层状结构,适合于锂离子的存储,与传统的锰酸锂、钴酸锂、磷酸铁锂等正极材料相比,具有高的理论比容量、功率密度以及价格低廉、原材料丰富等优势,在作为锂离子电池正极材料方面备受关注。但V_2O_5低的固有电导率及锂离子扩散系数,导致其容量保持率低和倍率性能差;此外,充放电过程中反复的相变会引起结构的不稳定,而且氧化钒会部分溶于电解液,因此表现出差的循环性能。正是由于这些制约因素的存在,对V_2O_5的固有缺陷进行改性研究以提高氧化钒正极材料的电化学性能成为重要的研究热点。将氧化钒进行纳米化以增大比表面积和缩短离子扩散距离,同时通过复合、掺杂改性等方法提高材料的导电性和循环稳定性,从而使V_2O_5正极材料表现出优异的电化学性能成为可能。文章从氧化钒电极材料纳米化,在纳米化的基础上复合导电材料,调节工作电压窗口,掺杂金属离子这四类方法阐述对氧化钒电化学性能的改善,以及各种方法对电极电化学性能的影响。     

锂离子电池中钒氧化物电极材料的研究现状

综述了钒氧化物在锂离子电池中的应用,重点介绍了V₂O₅、V₆O₁₃、VO₂、V₃O₇、V₆O₁₄的结构、制备方法以及其锂离子电池的电化学性质,说明了V₄O₉、V₂O₃难在锂离子电池中应用的原因,讨论了钒氧化物作锂离子电池的正极材料的优点以及存在的问题,最后提出钒氧化物有希望成为实用的锂离子电池阴极材料.     

Layered Transition Metal Dichalcogenide-Based Nanomaterials for Electrochemical Energy Storage

The rapid development of electrochemical energy storage (EES) systems requires novel electrode materials with high performance. A typical 2D nanomaterial, layered transition metal dichalcogenides (TMDs) are regarded as promising materials used for EES systems due to their large specific surface areas and layer structures benefiting fast ion transport. The typical methods for the preparation of TMDs and TMD-based nanohybrids are first summarized. Then, in order to improve the electrochemical performance of various kinds of rechargeable batteries, such as lithium-ion batteries, lithium–sulfur batteries, sodium-ion batteries, and other types of emerging batteries, the strategies for the design and fabrication of layered TMD-based electrode materials are discussed. Furthermore, the applications of layered TMD-based nanomaterials in supercapacitors, especially in untraditional supercapacitors, are presented. Finally, the existing challenges and promising future research directions in this field are proposed.     

Application and exploration of nanofibrous strategy in electrode design

The key to develop high specific energy rechargeable batteries is development of new electrode materials.The existing electrode materials still have many problems: the shuttle effect and poor conductivity of the sulfur cathode,the inevitable volume expansion of the silicon anode and the lithium dendrite of the lithium metal anode that cause short circuits,etc.Nanofibers,as active electrical materials,conductive additives and electrode bodies,can play multiple roles in electrode design.More interestingly,nanofibers can be functionalized to obtain better controllable properties (i.e.,electrolyte affinity,pore size distribution and surface electronic structure),thereby further enhancing electrochemical performance.In this article,the latest research progress in electrode design based on nanofibers is reviewed,including processing methods,structure,morphology and electrochemical performance.The key problems affecting the electrochemical performance of the electrode are also discussed,such as the preparation process,atomic structure,electrical conductivity,surface area and pore distribution of nanofibers,to provide reference points for nanofibers in excellent electrode design.     

Metal Oxide Hollow Nanostructures for Lithium‐ion Batteries

Metal oxide hollow structures have received great attention because of their many promising applications in a wide range of fields. As electrode materials for lithium‐ion batteries (LIBs), metal oxide hollow structures provide high specific capacity, superior rate capability, and improved cycling performance. In this Research News, we summarize the recent research activities in the synthesis of metal oxide hollow nanostructures with controlled shape, size, composition, and structural complexity, as well as their applications in LIBs. By focusing on hollow structures of some binary metal oxides (such as SnO₂, TiO₂, Fe₂O₃, Co₃O₄) and complex metal oxides, we seek to provide some rational understanding on the effect of nanostructure engineering on the electrochemical performance of the active materials. It is thus anticipated that this article will shed some light on the development of advanced electrode materials for next‐generation LIBs.     

柔性储能电池电极的设计、制备与应用EI北大核心CSCD

随着便携式、可穿戴电子器件的迅速发展,柔性储能器件的研究逐渐转向微型化、轻柔化和智能化等方向。同时人们对器件的能量密度、功率密度和力学性能有了更高的要求。电极材料作为柔性储能器件的核心部分,是决定器件性能的关键。柔性储能电子器件的发展,又迫切需要新型电池技术和快速、低成本且可精准控制其微结构的制备方法。因此,柔性锂/钠离子电池、柔性锂硫电池、柔性锌空电池等新型储能器件的研发成为目前学术界研究的热点。本文论述了近年来柔性储能电池电极的研究现状,着重对柔性电极材料的设计(独立柔性电极和柔性基底电极)、不同维度柔性电极材料的制备工艺(一维材料、二维材料和三维材料)和柔性储能电极的应用(柔性锂/钠离子电池、柔性锂硫电池、柔性锌空电池)进行对比分析,并对电极材料的结构特性和电化学性能进行了讨论。最后,指出了柔性储能器件目前所面临的问题,并针对此类问题展望了柔性储能器件未来的重点在于新型固态电解质的研发、器件结构的合理设计及封装技术的不断优化。     

锰氧化物的构造、合成及在锂离子二次电池正极材料的应用

锰氧化物通常以各种隧道构造、层状构造的化合物存在。这些锰氧化物作为锂离子二次电池正极材料显示了优越的电化学性质，其电气特性依据锰氧化物结晶构造和合成条件的不同而存在很大的差异。本文对于隧道状及层状锰氧化物的结晶构造、合成及其作为锂离子二次电池正极材料所显示的电气特性等进行了评述。     

Lithium intercalation in KxTi8O16 compounds

Several bronzes K_xTi₈O₁₆ have been prepared from K_1.64(1)Ti₈O₁₆ by means of oxidative reactions. These bronzes have been intercalated with lithium by electrochemical methods in order to test their performances as electrode materials in lithium rechargeable batteries. The main result is that although the maximum capacity (260 Ah kg⁻¹) is reached in the compound with the lowest potassium content, a low reversibility and high polarisation are obtained. Bronzes with intermediate potassium content are more attractive for applications in rechargeable lithium batteries. These compounds maintain an acceptable capacity (200 Ah kg⁻¹) while having high cyclability and low polarisation. The application should be addressed to anode materials rather than to cathode due to the low voltage (1.75 V) obtained during the intercalation reaction.     

Li_4Ti_5O_(12)的溶胶-凝胶合成及性能研究

研究了一种制备锂离子电池负极材料的Li4Ti5O12新工艺.以醋酸锂和钛酸丁酯为原料,异丙醇为溶剂,采用溶胶-凝胶法制备前驱体,再通过一定的热处理后制备了锂离子电池负极材料Li4Ti5O12采用XRD、SEM及电化学性能测试等分析手段考察了不同热处理温度对产品性能的影响.结果发现,经过850℃热处理24h后得到的产品粒径分布均匀、结晶度好;并且表现出较好的电化学性能,在1～2.5V之间充放电,0.1、1.0和2.0C首次放电比容量分别达到174.5、154.9和124.38mAh/g,并且大电流充放电时具有较好的循环性能.研究表明该方法是适合制备高活性的Li4Ti5O12工艺方法.     

Transition Metal on the Electrochemical Performances of Some Intermetallic Anodes for Lithium Ion Batteries

Some transition metal antimonides were prepared by levitation melting and subsequent ball-milling. The electrochemical behaviors of these materials as new candidate negative electrode materials in lithium ion secondary batteries were investigated. It was found that they exhibited significantly larger volumetric capacity than carbon-based materials. The formation and composition of solid electrolyte interface (SEI) film were characterized by electrochemical impedance spectroscopy (EIS) and Fourier transform infra-red (FTIR) spectroscopy.     

Effect of Transition Metal on the Electrochemical Performances of Some Intermetallic Anodes for Lithium Ion Batteries

Some transition metal antimonides were prepared by levitation melting and subsequent ball-milling. The electrochem-ical behaviors of these materials as new candidate negative electrode materials in lithium ion secondary batteries wereinvestigated. It was found that they exhibited significantly larger volumetric capacity than carbon-based materi-als. The formation and composition of solid electrolyte interface (SEI) film were characterized by electrochemicalimpedance spectroscopy (EIS) and Fourier transform infra-red (FTIR) spectroscopy.     

锂离子电池锡基负极材料研究进展

综述了锂离子电池锡基负极材料的研究进展,锡基钢极材料可分为氧化物,复合氧化物,合金三类,其储锂机理都为合金机理,对氧化物的丰重于电极反应的详细过程,对复合氧化物的研究重点则是储锂机理,而锡合金则是最有希望进入商业化市场的锡基钢极材料,其中锡与锂可逆形成合金,另一不与锂反应的金属作为导电基体与框架,容纳合金以改善循环性能。     

纳米结构的氧化钒作锂离子电池阴极材料的研究进展

V2O5具有独特的层状结构,适合于锂离子的存储,与传统的锰酸锂、钴酸锂、磷酸铁锂等阴极材料相比,表现出高的理论比容量和功率密度,作为锂离子电池阴极材料备受青睐。但它自身的结构不稳定、电导率低,导致实际比容量远低于理论值,且循环稳定性不能长期维持。正是由于这些制约因素,V2O5作锂离子电池阴极材料还有很大的研究价值。而利用各种制备方法将V2O5制备成具有各种纳米结构的材料,如一维的纳米线、纳米管等,二维的纳米片,三维的纳米空心球、纳米花等,改善材料固有的形貌结构,增大比表面积,增强锂离子在电极材料中的嵌入/脱出性能,提高储锂能力和比容量,同时通过掺杂改性等方法增强材料的导电性和循环稳定性,使V2O5作为锂离子电池阴极材料表现出优异的电化学性能成为可能。介绍了V2O5的晶体结构及其作为电极材料的纳米结构,以及不同的纳米结构对电极材料电化学性能的影响。     

锂硫聚合物二次电池关键材料研究进展

报告了在复合型纳米硫正极材料、纳米储锂合金负极材料和用原位合成工艺掺入纳米二氧化硅的凝 胶型聚合物电解质的研制方面所取得的进展;所研制的复合型纳米硫正极材料与凝胶电解质及锂金属负极配合 制成扣式实验电池进行测试,容量已达到７００mAh桙g,发现该材料放电电压是现有锂钴氧材料放电电压的一半, 双电池串联可以与现有锂钴氧材料电池互换;采用微乳液新工艺合成的Cu－Sn纳米合金材料,以石墨与金属锡 复合的材料,以及以金属氧化物作为原料,采用乳液法制备碳微球镶嵌金属锡的球形复合材料等高容量负极材 料取得了较大的进展     

Rapid and Low‐Temperature Salt‐Templated Production of 2D Metal Oxide/Oxychloride/Hydroxide

2D materials have played an important role in electronics, sensors, optics, electrocatalysis, and energy storage. Many methods for the preparation of 2D materials have been explored. It is crucial to develop a high‐yield, rapid, and low‐temperature method to synthesize 2D materials. A general, fast (5 min), and low‐temperature (≈100 °C) salt (CoCl₂·6H₂O)‐templated method is proposed to prepare series of 2D metal oxides/oxychlorides/hydroxides in large scale, such as MoO₃, SnO₂, SiO₂, BiOCl, Sb₄O₅Cl₂, Zn₂Co₃(OH)₁₀ 2H₂O, and ZnCo₂O₄. The as‐synthesized 2D materials possess an ultrathin feature (2–7 nm) and large aspect ratios. Additionally, these 2D metal oxides/oxychlorides/hydroxides exhibit good electrochemical properties in energy storage (lithium/sodium‐ion batteries) and electrocatalysis (hydrogen/oxygen evolution reaction).     

MOF‐Derived Metal Oxide Composites for Advanced Electrochemical Energy Storage

Over the past two decades, metal–organic frameworks (MOFs), a type of porous material, have aroused great interest as precursors or templates for the derivation of metal oxides and composites for the next generation of electrochemical energy storage applications owing to their high specific surface areas, controllable structures, and adjustable pore sizes. The electrode materials, which affect the performance in practical applications, are pivotal components of batteries and supercapacitors. Metal oxide composites derived from metal–organic frameworks possessing high reversible capacity and superior rate and cycle performance are excellent electrode materials. In this Review, potential applications for MOF‐derived metal oxide composites for lithium‐ion batteries, sodium‐ion batteries, lithium–oxygen batteries, and supercapacitors are studied and summarized. Finally, the challenges and opportunities for future research on MOF‐derived metal oxide composites are proposed on the basis of academic knowledge from the reported literature as well as from experimental experience.     

硅材料在锂离子电池中的应用研究进展

硅材料作为锂离子电池负极材料具有比容量大的优点,是高容量锂离子负极材料的研究热点之一.综述了近年来锂离子电池硅负极材料的研究进展.分别对硅及含硅材料作为锂离子电池负极材料的发展过程、充放电特性、储锂机理及影响其储锂的各因素进行了分析和总结,并对其存在的问题进行了分析.探讨了采用不同复合物、不同制备方法和合成硅化物等改性方法来提高其循环性能的可行性.指出纳米硅基复合物将是硅负极材料最有希望的发展方向.     

Recent advances in electrospun carbon nanofibers and their application in electrochemical energy storage

Carbon nanofibers (CNFs) have been widely used in electrochemical energy storage devices because of their excellent conductivities, extremely large surface areas and structural stability. In energy storage devices like rechargeable batteries and supercapacitors, CNFs play multi-functional roles as active electrode materials, conductive additives and substrates for supporting active metal (oxides). Electrospinning offers a low cost and scalable technique to fabricate CNFs and their hybrids with tunable nanostructures. This paper summarizes various design strategies for producing random, aligned and core/shell structured fibers, and elucidates the influences of polymer precursors, processing parameters, conductive additives and catalysts on functional, morphological and structural characteristics of CNFs. The current start-of-the-art developments for applications in Li-ion batteries, supercapacitors, Na-ion batteries, Li–O₂ batteries and Li–S batteries are reviewed. Key issues that affect the electrochemical performance of the electrodes, such as the chemical and atomic structures, electrical conductivities, surface areas and pore size distribution of CNFs, and the particle size, shape and dispersion of metal (oxides) encapsulated in CNFs, are discussed and their solutions suggested. Future prospects on further optimization of the structure and performance, and challenges encountered in large-scale applications of electrospun CNFs are proposed.