Improvement of cyclic behavior of a ball-milled SiO and carbon nanofiber composite anode for lithium-ion batteries

The cyclic performance of a composite SiO and carbon nanofiber (CNF) anode was examined for lithium-ion batteries. SiO powder of several micrometers was pulverized using high energy mechanical milling. The SiO was ball-milled for 12 h with CNF to produce a composite electrode material that exhibited excellent cycling performance. A reversible capacity of approximately 700 mAh g⁻¹ was observed after 200 cycles. The excellent cyclic performance was discussed with respect to the change of the valence state of Si by ball-milling. A large irreversible capacity at the first cycle for the SiO/CNF composite electrode was reduced to 2% by chemically pre-charging with a lithium film attached to the rim of the electrode.     

In situ electrochemical synthesis of lithiated silicon–carbon based composites anode materials for lithium ion batteries

Most composite anode systems research on lithium ion batteries to date focus on pristine unalloyed Si as the electrochemically active component combined with a suitable matrix component that is electrochemically inactive or relatively inactive to lithium ions. Herein, we report the generation of composites by electrochemical synthesis in situ, denoted as Li–Si/C based on Li–Si alloys synthesized as dispersoids in a carbon (C) matrix, as potential anode materials for lithium ion batteries. The electrochemical performance of the Li–Si/C composite of different compositions generated has been systematically studied in order to identify a suitable Li–Si–C composition that could be most effective as a lithium ion anode. The resultant alloy would also exhibit stable electrochemical capacities while expecting to deliver high energy density during discharge with suitable cathode systems. This study shows that the Li–Si/C composite of composition 64 at.% C–21.6 at.% Li–14.4 at.% Si, comprised of Li–Si alloy of compositions in the vicinity of Li–40 at.% Si dispersed in the C matrix cycled within the stable potential window of 0.02–0.5 V, has the potential characteristics of being a promising anode material displaying excellent capacity retention (0.13% loss per cycle) with high specific capacity (700 mA h g⁻¹), and also expected to deliver high energy density during discharge in the full cell configuration employing a suitable cathode.     

Enhanced cycle performance of SiO-C composite anode for lithium-ion batteries

A silicon monoxide (SiO)-carbon composite prepared by ball-milling and pyrolysis is evaluated as an anode material for lithium-ion batteries. Electrochemical tests demonstrated that the first charge and discharge capacities of the material are about 1050 and 800 mAh g⁻¹, respectively, with a first-cycle efficiency of 76%. The disproportionation reaction of pure SiO into Si and SiO₂ during pyrolysis is confirmed by means of XRD and ²⁹Si MAS NMR. The cycle performance of this material shows an excellent reversible capacity retention of 710 mAh g⁻¹ over 100 cycles without any potential or capacity restrictions. This improved cycle performance is attributed to the stable microstructure, enhanced electrical contact afforded by the pyrolyzed carbon, and the amorphous phase transformation of the active material during cycling.     

Comparative studies of MCMB and CC composite as anodes for lithium-ion battery systems

Mesocarbon microbead (MCMB 2528) and CC composite have been investigated as anodes for lithium-ion batteries using half-cells with lithium counter electrode and three electrode cell systems containing LiCoO₂ cathode and lithium reference electrodes in 1 M LiPF₆ electrolyte (EC/DMC 1:1 v/v). The test results show that the practical capacity of CC composite anode is 50% higher than that of MCMB-based anode (based on total anode weight). The irreversible capacity loss of CC composite is significantly lower than that of MCMB carbon. Lithium-ion cells made with CC composite anode can accept repeated overdischarge without performance deterioration. The extra capacity of CC composite can be utilized to improve energy density and safety issues related to overcharge of lithium-ion cells. Differential scanning calorimetry (DSC) results indicates that the thermal stability of fully charged CC composite anode (lithiated anode) is much better than that of fully charged MCMB anode.     

钛酸锂基锂离子电池及其健康状态研究进展

锂离子电池的高功率密度和高能量密度等特性使其成为电动汽车能源和新能源电网储能的重要载体。功率性能和安全特性是锂离子电池发展的两个主要挑战。钛酸锂Li₄Ti₅O₁₂材料因具有良好的结构稳定性、安全性能、长循环寿命、高功率特性和高低温放电性能,被认为是锂电池负极材料的良好备选。综述了以钛酸锂材料为负极的锂离子电池的相关工作,介绍了钛酸锂材料的结构、电化学特性、制备方法和作为电池负极材料面临的主要问题,重点介绍了钛酸锂负极电池的全电池性能和健康状态研究等方面。     

Research progress on Si/C composites as anode for lithium ion batteries

硅基负极材料具有比容量高、电压平台低、环境友好、资源丰富等优点,有望替代石墨负极应用于下一代高比能锂离子电池。但是硅的导电性较差,且在充放电过程中存在巨大的体积效应,极易导致电极极化、材料粉化、SEI膜重构、库仑效率低和容量持续衰减。硅和碳复合能很好地综合两者的优势,形成结构稳定、循环性好及容量高的负极材料。本文从不同维度的硅（SiNPs、SiNTs/SiNWs、SiNFs、Bulk Si）与碳复合这一角度,综述了硅碳复合材料在结构设计、制备工艺、电化学性能等方面的最新研究进展,并对未来的硅碳复合材料的研究工作进行了展望。     

The cycle life investigation for spinel LiNi0.5Mn1.5O4 full cells

分别以石墨和钛酸锂为负极活性物质,制备了尖晶石镍锰酸锂的32131型圆柱锂离子电池.石墨负极电池和钛酸锂负极电池容量分别为7.5 A·h和5.5 A·h,质量能量密度分别达到152 W·h/kg和81 W·h/kg.常温充放电循环测试结果表明,石墨和钛酸锂两种负极体系电池循环寿命将分别达到400次和1000次,这种循环寿命的差别主要体现在负极上,即正极材料中溶解的Mn在石墨负极表面沉积并持续催化SEI膜生成,减少了电池中可使用的活性Li⁺,进而导致电池寿命快速衰减;相比而言,钛酸锂负极表面不存在明显SEI,同时正极过量设计电池也使得钛酸锂体系电池的镍锰酸锂与电解液间的界面副反应低于石墨体系的负极过量设计电池.     

High performance silicon carbon composite anode materials for lithium ion batteries

Silicon and silicon containing compounds are attractive anode materials for lithium batteries because of their low electrochemical potential vs. lithium and high theoretical capacities. In this work the relationship between the electrochemical performance of silicon powders and their particle sizes was studied. It is found that the material with nano particle sizes gives the best performance. New silicon/carbon composite anode materials were synthesized and their structures and electrochemical performance were investigated. The results of these studies are reported in this paper.     

Research progress on the Li-excess Mn-based cathode materials with high capacity for lithium-ion battery

富锂锰基正极材料因具有高的放电比容量,有望成为下一代400 W·h/kg动力电池最有前景的正极材料。本文简要介绍了本研究团队在富锂锰基正极材料方面的研究进展。通过团队多年研发,材料的首次不可逆容量、倍率性能、循环稳定性得到明显的改善,而且,电压衰减被有效的抑制。同时,研制出基于富锂锰基正极材料和纳米硅碳负极材料的新型24A·h高容量锂离子电池,其质量能量密度达到374 W·h/kg,体积能量密度达到  577 W·h/L。     

In-situ synthesis of two-dimensional sheet-like MoO2/NPC@rGO as advanced anode for alkali metal ion batteries

MoO₂ anode displays excellent potential in the alkali ion batteries owing to its large capacity, high conductivity and stability. However, exploiting the stable and high performance MoO₂ anode endowed with triple roles for the storage of lithium/sodium/potassium ions is still a challenge. Herein, a two-dimensional sheet-like MoO₂/NPC@rGO composites were in-situ synthesized and utilized as anode materials for alkali metal ion batteries. Applied as an anode in lithium ion batteries (LIBs), superior cycling capability and rate performance were obtained, which kept a large reversible capacity of 1233.1 mAh/g in the 200th cycle at 100 mA/g. Impressively, it displayed superior long cycling performance over 1000 cycles with a 249.5 mAh/g capacity at a high current density of 10 A/g. Simultaneously, MoO₂/NPC@rGO displayed enhanced electrochemical performance both in sodium and potassium ion batteries (NIBs/KIBs). Furthermore, the ex-situ X-ray photoelectron spectroscopy results verified the reversible reaction during Li⁺ insertion-extraction process. The improved energy storage properties were attributed to the typical two dimensional structure and synergistic effects between various constituents, which suppressed the volume change, created more active sites, increased the conductivity and facilitated reaction kinetics. More significantly, our design provides a simple and green route to synthesize transition metal oxide anode and promote their applications in energy storage devices.     

Electrochemical properties of novel O3-NaCu1/9Ni2/9Fe1/3Mn1/3O2 as cathode material for sodium-ion batteries

由于钠具有资源丰富和成本低廉的优势,钠离子电池再次受到科学界和工业界的广泛关注。发展低成本、性能优异的正极材料对于钠离子电池至关重要。本文通过向O3-Na0.90[Cu0.22Fe0.30Mn0.48]O2材料中引入容易变价的Ni2+得到一种不含Mn3+的钠离子电池新型正极材料O3-NaCu1/9Ni2/9Fe1/3Mn1/3O2,该材料具有127 mA•h/g可逆比容量和3.1 V平均放电电压。由该正极与硬碳球负极组装成全电池具有248 W•h/kg的理论能量密度,高达93%的能量转化效率和优异的循环性能。     

基于LLZO的复合电解质对Li-S电池穿梭效应的抑制

相对于传统锂离子电池,锂硫电池具有高比容量、高能量密度、环境友好等特点,因而在作为未来的动力电池和储能电池上被寄予厚望。但是,目前的锂硫电池存在穿梭效应、硫利用率低、充放电体积变化大等问题。本工作主要针对硫的穿梭效应、硫在负极材料沉积等问题开展研究。首先制备出室温离子传导率为6.4×10-4 S/cm的含锂石榴石（LLZO）固态电解质;再引入LLZO固态电解质作为隔膜,使用石墨烯气凝胶复合硫正极组装电池进行测试。充放电循环测试结果表明,该电池结构可以解决锂硫电池难以有效充电的问题,获得了接近100%的库仑效率。此外,采用XRD、SEM等检测手段分析了充放电循环后LLZO隔膜的微观物相结构,证明了LLZO能够有效阻挡多硫化物,抑制穿梭效应。     

Multiporous core-shell structured MnO@N-Doped carbon towards high-performance lithium-ion batteries

It is imminently to seek for high energy density in addition to a sensational lifetime of lithium-ion batteries (LIBs) to meet growing requisition in the energy storage application. Anode containing metal oxide composite is being thoroughly investigated for their higher capacity than that of the commercial graphite. A multiporous core-shell structured metal oxide composite anode possessing the excellent capacity and superb lifespan for LIBs is designed. In detail, metal oxide (i.e., MnO) is encapsulated in N-doped carbon shell (MnO@N–C) via coprecipitation-annealing technique. During annealing, abundant void space among MnO cores/between MnO cores and N–C shells is obtained. This space can efficaciously buffer volume changes of MnO upon cycles. Benefiting from the unique structure and heteroatom doping, the capacity of MnO@N–C microcube anode exhibits 576 mAh g⁻¹ at 5 A g⁻¹ with an ultra-long lifespan more than 3500 cycles. The connection between the electrode characteristics and structure is concurrently examined by adopting kinetic analysis. Finally, a full lithium-ion battery is presented, applying the MnO@N–C (anode) and Nick-rich layered oxide (cathode). It is believed that structural designing with heteroatom doping can be utilized in vaster fields for superior capabilities.     

Recent research progress of metal compounds as anode materials for sodium-ion batteries

钠离子电池具有钠资源存储丰富、价格低廉等优点,是一种极具发展前景的储能装置,因此成为当下研究热点。钠离子电池的电化学性能主要取决于正负极材料。但是,钠离子较大的半径使其在电极材料中可逆地嵌入/脱出更为困难。而金属化合物材料作为储钠负极材料时,遵循转化反应机制,并表现出较高的理论比容量,因而受到研究人员的广泛关注。本文综述了金属氧化物、金属硫化物、金属磷化物等几种金属化合物负极材料的储钠机制和研究进展,探讨了金属化合物材料的储钠性能,阐明了金属化合物作为理想的储钠负极材料的优势,最后对金属化合物材料的研究前景进行了展望。     

Ordered CoO/CMK-3 nanocomposites as the anode materials for lithium-ion batteries

A novel ordered mesoporous carbon hybrid composite, CoO/CMK-3, is prepared by an infusing method using Co(NO₃)₂·6H₂O as the cobalt source. The products are characterized by X-ray diffraction, transmission electron microscopy and N₂ adsorption-desorption analysis techniques. It is observed that the CoO nanoparticles are loaded in the channels of mesoporous carbon. The mesopore structure of CMK-3 is destroyed gradually with increasing of the CoO content. The electrochemical properties of samples as the anode materials for lithium-ion batteries are studied by galvanostatic method. The results show that the CoO/CMK-3 composites have higher reversible capacities (more than 700 mAh g⁻¹) and better cycle performance in comparison with the pure mesoporous carbon (CMK-3). Based on the above results, a mechanism is proposed to explain the reason of such a substantial improvement of electrochemical performance in the CoO/CMK-3 composites.     

Development of long life lithium ion battery for power storage

With the aim of developing lithium ion batteries with a long life and high efficiency for power storage, we experimentally evaluated combinations of cathode and anode active materials, in which batteries are able to obtain over 4000 cycles or 10 years of life. An acceleration method was evaluated using coin cells. We found that changing the current density was effective for evaluating battery life, since the logarithm of the cycle life showed a linear relationship to current density. Based on the current density increasing method, various combinations of cathode and anode active materials were tested. The cell system of LiCoO₂/Li_4/3Ti_5/3O₄ clearly showed a long life of about 4000 cycles. The energy density of the cell using the Li_4/3Ti_5/3O₄ anode is obviously smaller than that using a graphite anode, the cell with Li_4/3Ti_5/3O₄ anode was thought to have some merit especially in the large-scale-layer-built type battery by the applicability of the Al anode collector and a light weight battery case.     

Rechargeable lithium sulfide electrode for a polymer tin/sulfur lithium-ion battery

In this work we investigate the electrochemical behavior of a new type of carbon-lithium sulfide composite electrode. Results based on cyclic voltammetry, charge (lithium removal)-discharge (lithium acceptance) demonstrate that this electrode has a good performance in terms of reversibility, cycle life and coulombic efficiency. XRD analysis performed in situ in a lithium cell shows that lithium sulfide can be converted into sulfur during charge and re-converted back into sulfide during the following discharge process. We also show that this electrochemical process can be efficiently carried out in polymer electrolyte lithium cells and thus, that the Li₂S-C composite can be successfully used as cathode for the development of novel types of rechargeable lithium-ion sulfur batteries where the reactive and unsafe lithium metal anode is replaced by a reliable, high capacity tin-carbon composite and the unstable organic electrolyte solution is replaced by a composite gel polymer membrane that is safe, highly conductive and able to control dendrite growth across the cell. This new Sn-C/Li₂S polymer battery operates with a capacity of 600 mAh g⁻¹ and with an average voltage of 2 V, this leading to a value of energy density amounting to 1200 Wh kg⁻¹.     

Electrochemical properties of Si–Zn–C composite as an anode material for lithium-ion batteries

A Si–Zn–C composite material is prepared by mechanical ball-milling and investigated as an anode material for lithium-ion batteries. Electrochemical tests show that the first charge and discharge capacities are approximately 852 and 607 mAh g⁻¹, respectively, and that 91% of the initial discharge capacity of 607 mAh g⁻¹ can be maintained for up to 40 cycles. This improved cycling performance is attributed to the use of the third element Zn. Li₂ZnSi is partially formed at the interface between Si and Zn and graphite to provide superior cycling performance compared with that of the binary system.     

Study on the anode behavior of Sn and Sn–Cu alloy thin-film electrodes

Anodes based on tin metal powder offer large specific capacity, but also exhibit large irreversible capacity and poor cycle performance. In order to use them as a negative electrode for lithium secondary batteries, we focused on the electrodepositing process and investigated an electrodeposited tin layer on copper foil. In the full charge–discharge condition, charging and discharging between 0 and 2.0 V versus Li/Li⁺, the first discharge capacity was 940 mAh g⁻¹, which was 2.5 times as large as that of graphite, and the coulomb efficiency in the first cycle was 93%, but its cycle performance was not improved.In order to enhance the interface strength between the active material and the copper foil, we investigated an anode which was fabricated by annealing an as-deposited anode. In the full charge–discharge condition, the first charge–discharge characteristics were almost equivalent to the as-deposited anode, and the retention capacity ratio after 10 cycles was improved from 20 to 94%. It is considered that this improvement resulted from the formation of two different tin–copper intermetallic compound layers between the tin layer and the copper current collector due to the heat treatment.A small cell using this annealed anode as a negative electrode was also investigated. This cell offered good cycle performance for the first 20 cycles.     

A brief overview of secondary zinc anode development: The key of improving zinc‐based energy storage systems

Electricity will increasingly be produced from sources that are geographically decentralized and/or intermittent in their nature. In consequents, there is an urgent need to increase the storage of energy to guarantee the continuity of energy supply. Rechargeable zinc‐air battery is a promising technology due to the high theoretical energy density and the abundant and environmentally benign materials that are used. In the state of the art, the information about secondary zinc anode for rechargeable zinc‐air batteries is scarce. The main development of the technology has been lately concentrated on the bifunctional air electrodes while the used zinc anode is mainly based on a planar zinc electrode providing low specific energy densities for the full system. This overview compiles the available information in the literature regarding the development and manufacturing of zinc anodes for electrical rechargeable batteries applications, where secondary porous zinc electrodes are generally desired. In this context, the zinc‐based anode electrode composition (namely, active material, binder, conductive material, current collector, and additives), pretreatments, and processing techniques are described and their impact on the zinc anode performance analyzed.