Interconnected sandwich structure carbon/Si-SiO_2/carbon nanospheres composite as high performance anode material for lithium-ion batteries

In the present work,an interconnected sandwich carbon/Si-SiO_2/carbon nanospheres composite was prepared by template method and carbon thermal vapor deposition(TVD).The carbon conductive layer can not only efficiently improve the electronic conductivity of Si-based anode,but also play a key role in alleviating the negative effect from huge volume expansion over discharge/charge of Si-based anode.The resulting material delivered a reversible capacity of 1094 mAh/g,and exhibited excellent cycling stability.It kept a reversible capacity of 1050 mAh/g over 200 cycles with a capacity retention of 96%.     

Interconnected sandwich structure carbon/Si-SiO2/carbon nanospheres composite as high performance anode material for lithium-ion batteries

In the present work,an interconnected sandwich carbon/Si-SiO2/carbon nanospheres composite was prepared by template method and carbon thermal vapor deposition（TVD）.The carbon conductive layer can not only efficiently improve the electronic conductivity of Si-based anode,but also play a key role in alleviating the negative effect from huge volume expansion over discharge/charge of Si-based anode.The resulting material delivered a reversible capacity of 1094 mAh/g,and exhibited excellent cycling stability.It kept a reversible capacity of 1050 mAh/g over 200 cycles with a capacity retention of 96%.     

Nano-structured phosphorus composite as high-capacity anode materials for lithium batteries

More than LiP service: The adsorption of red phosphorus into porous carbon provides a composite anode material for lithium-ion batteries. The amorphous nano phosphorus, in the carbon matrix, shows highly reversible lithium storage with high coulombic efficiencies and stable cycling capacity of 750?mAh per gram composite.     

Investigation of PZT-5H and PZT-8 type piezoelectric effect on cycling stability on Si-MWCNT containing anode materials

Silicon (Si) containing materials cannot be used in commercial lithium ion batteries due to the mechanical stress problem triggered by volume expansion during cycling. The high-volume change causes mechanical instability of Si anode materials during charging/discharging, resulting fast capacity fading. It is thought that piezoelectric materials can be a solution for the volume expansion problem because of their ability to generate electric field when pressure is applied on them. For this purpose, PZT-8 and PZT-5H type piezoelectric materials were mixed with silicon and multiwalled carbon nanotube (MWCNT) to obtain anode composites and tested electrochemically versus lithium metal. The piezoelectiric effect on the electrochemical activity of these anodes is investigated by preparing the anode composite without any piezoelectric material additive (Sample #3). At the end of the 50 charge/discharge cycles, the capacities reached 420 mAh/g, 300 mAh/g and 100 mAh/g for PZT-8-added, PZT-5H-added and no-PZT samples, respectively. These results showed that PZT addition improves capacity performance of Si-MWCNT anodes. Additionally, the obtained anode composites were characterized with X-ray diffraction and scanning electron microscopy.     

Nanostructured Carbon/Antimony Composites as Anode Materials for Lithium‐Ion Batteries with Long Life

A series of nanostructured carbon/antimony composites have been successfully synthesized by a simple sol–gel, high‐temperature carbon thermal reduction process. In the carbon/antimony composites, antimony nanoparticles are homogeneously dispersed in the pyrolyzed nanoporous carbon matrix. As an anode material for lithium‐ion batteries, the C/Sb10 composite displays a high initial discharge capacity of 1214.6 mAh g^?1 and a reversible charge capacity of 595.5 mAh g^?1 with a corresponding coulombic efficiency of 49 % in the first cycle. In addition, it exhibits a high reversible discharge capacity of 466.2 mAh g^?1 at a current density of 100 mA g^?1 after 200 cycles and a high rate discharge capacity of 354.4 mAh g^?1 at a current density of 1000 mA g^?1. The excellent cycling stability and rate discharge performance of the C/Sb10 composite could be due to the uniform dispersion of antimony nanoparticles in the porous carbon matrix, which can buffer the volume expansion and maintain the integrity of the electrode during the charge–discharge cycles.     

Copper-cobalt-nickel oxide nanowire arrays on copper foams as self-standing anode materials for lithium ion batteries

Numerous scientists are in the pursuit of energy storage materials with high energy and high power density by assembly of electrochemically active materials into conductive scaffolds, owing to the emerging need for next-generation energy storage devices. In this architectures, the active materials bonded to the conductive scaffold can provide a robust and free-standing structure, which is crucial to the fabrication of materials with high gravimetric capacity. Thus, hierarchical copper-cobalt-nickel ternary oxide (CuCoNi-oxide) nanowire arrays grown from copper foam were successfully fabricated as free-standing anode materials for lithium ion batteries (LIBs). CuCoNi-oxide nanowire arrays could provide more active sites owing to the hyperbranched structure, leading to a better specific capacity of 1191 mAh/g, cycle performance of 73% retention in comparison to CuO nanowire structure, which exhibited a specific capacity of 1029 mAh/g and capacity retention of 43%, respectively.     

Preparation of Carbon Nanowall and Carbon Nanotube for Anode Material of Lithium-Ion Battery

Carbon nanowall (CNW) and carbon nanotube (CNT) were prepared as anode materials of lithium-ion batteries. To fabricate a lithium-ion battery, copper (Cu) foil was cleaned using an ultrasonic cleaner in a solvent such as trichloroethylene (TCE) and used as a substrate. CNW and CNT were synthesized on Cu foil using plasma-enhanced chemical vapor deposition (PECVD) and water dispersion, respectively. CNW and CNT were used as anode materials for the lithium-ion battery, while lithium hexafluorophosphate (LiPF₆) was used as an electrolyte to fabricate another lithium-ion battery. For the structural analysis of CNW and CNT, field emission scanning electron microscope (FE-SEM) and Raman spectroscopy analysis were performed. The Raman analysis showed that the carbon nanotube in composite material can compensate for the defects of the carbon nanowall. Cyclic voltammetry (CV) was employed for the electrochemical properties of lithium-ion batteries, fabricated by CNW and CNT, respectively. The specific capacity of CNW and CNT were calculated as 62.4 mAh/g and 49.54 mAh/g. The composite material with CNW and CNT having a specific capacity measured at 64.94 mAh/g, delivered the optimal performance.     

High lithiophilic nitrogen-doped carbon nanotube arrays prepared by in-situ catalyze for lithium metal anode

Lithium metal has a very outstanding theoretical capacity(3860 mAh/g) and is one of the most superior anode materials for high energy density batteries.However,the uncontrollable dendrite growth and the fo rmation of "dead lithium" are the important hidden dangers of short cycle life and low safety.However,the uncontrollable dendrite growth and the fo rmation of dead lithium leads to short cycle life and hidden dange r,which hinder its practical application.Controlling the nucleation and growth process of lithium is an effective strategy to inhibit lithium dendrite.Herein,a simple in situ self-catalytic method is used to construct nitrogen doped carbon nanotube arrays on stainless steel mesh(N-CNT@SS) as a lithium composite anode.The N-doped CNTs provide a great number of N-functional groups,which enhance the lithiophilic of anode and provide a large number of uniform nucleation sites,hence it has excellent structural stability for cycles.The arrays provide neat lithium-ion transport channels to uniform lithiumion flux and inhibits dendrite generation,revealed by the COMSOL multi-physics concentration field simulation.The N-CNT@SS composite anode sustain stable at 98.9% over 300 cycles at 1 mA/cm2.NCNT@SS as the anode is coupled LiFePO_4(LFP) as the cathode construct a full battery,demonstrating excellent cycling stability with a capacity of 152.33 mAh/g and capacity retaining ratio of 95.4% after 100 cycles at 0.5 C.     

锂离子电池用富锂层状正极材料

正极材料与负极材料是锂离子电池重要组成部分。目前锂离子电池负极材料比容量通常在300mAh/g以上,而正极材料比容量始终徘徊在150mAh/g。正极材料正在成为锂离子电池性能进一步提升的瓶颈。富锂层状正极材料是一类新型正极材料,其可逆容量在200mAh/g以上,其高容量特性引起人们的广泛关注。这类材料可以用xLi₂MO₃·(1-x)LiM'O₂ (M 为Mn, Ti, Zr之一或任意组合; M'为Mn, Ni, Co之一或任意组合; 0≤x≤1)形式表示。由于其组成与结构的特殊性,这类富锂层状正极材料的充放电机理也不同于其它含锂过渡金属氧化物正极材料。本文介绍富锂层状正极材料的合成、结构与充放电机理,重点介绍近年来通过改性提高其电化学性能方面的研究进展,指出目前富锂材料研究中存在的问题,探讨未来的研究重点。     

Agar-derived nitrogen-doped porous carbon as anode for construction of cost-effective lithium-ion batteries

Balancing cost and performance of porous carbon (PC) as anode for lithium-ion battery (LIBs) is the key to effectively promote commercial application. Herein, low-cost N-doped PC (NPC-Ts, T = 600, 750 and 900 °C) were facilely prepared in batches via one-pot pyrolysis of agar with different carbonization temperature. The NPC-750 with specific surface area of 2914 m²/g and N content of 2.84% exhibits an ultrahigh reversible capacity of 1019 mAh/g at 0.1 A/g after 100 cycles and 837 mAh/g at 1 A/g after 500 cycles. Remarkably, the resulting LIBs exhibit an ultrafast charge-discharge feature with a remarkable capacity of 281 mAh/g at 10 A/g and a superlong cycle life with a capacity retention of 87% after 5000 cycles at 10 A/g. Coupling with LiFePO₄ cathode, the fabricated lithium-ion full cells possess high capacity, excellent rate and cycling performances (125 mAh/g at 100 mA/g, capacity retention of 95%, after 220 cycles), highlighting the practicability of this NPC-750 as the anode materials.     

Cobalt oxyhydroxide/graphene oxide nanocomposite for amelioration of electrochemical performance of lithium/sulfur batteries

Cobalt oxyhydroxide combination with graphene oxide (CoOOH@GO) as a novel conductive matrix is developed for high performance lithium/sulfur batteries. Enhancement retention of polysulfide species into matrix of cobalt oxyhydroxide anchored on graphene oxide flakes by strong chemical binding of carbon-sulfur is demonstrated. Sulfur incorporated in the sheet-like morphology of CoOOH@GO delivers high initial discharge specific capacity of 1190.85 mAh/g, which raises 260 mAh/g with respect to graphene oxide/sulfur (GO/S) as a cathode material. Furthermore, CoOOH@GO/S maintains the average coulombic efficiency of 96 % after 300 cycles at 1 C rate with capacity retention of about 61 %. Good current rate capability of CoOOH@GO/S cathode reveals that the resulting composite is open platform for electrolyte diffusion and fast ion transportation leading to the improved electrochemical performance of lithium/sulfur batteries.     

Microporous carbon aerogel prepared through ambient pressure drying route as anode material for lithium ion cells

Carbon aerogel synthesized through a cost‐effective and easy method was evaluated and found to be a promising anode material for lithium ion cells. Carbon aerogel was prepared by carbonizing resorcinol–formaldehyde (RF) aerogel under inert atmosphere. Resorcinol–formaldehyde aerogel in turn was prepared through sol gel polymerization of resorcinol with formaldehyde using sodium carbonate as catalyst adopting ambient pressure drying route. The structure and the morphology of the prepared carbon aerogel are investigated using X‐ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and surface area determined using N₂–Brunauer–Emmett–Teller (BET) method. The TEM images reveal microporous morphology of the carbon aerogel particles. The evaluation of carbon aerogel as an anode material revealed promising specific capacity synergized with outstanding cyclability. The first cycle specific capacity was 288 mAh/g with an efficiency of 63% at C/10 rate. The material retained a capacity of 96.9% of the initial capacity with about 100% efficiency after 100 cycles, showing the excellent cyclability of the material. Copyright © 2017 John Wiley & Sons, Ltd.     

基于不同前驱体制备的硬碳负极材料的储锂性能

以聚丙烯腈、石油沥青和花生壳为前驱体,在1200℃下碳化制备三种不同的硬碳材料.通过扫描电子显微、X射线衍射、氮气吸附/脱附测试和拉曼光谱等方法探究不同前驱体所制备的硬碳材料的表面形貌和物相结构.通过恒流充放电测试考察了这三种硬碳负极材料的电化学性能.结果表明,花生壳基硬碳的初始放电比容量最高,但首圈库仑效率最低,石油...     

聚三苯胺/活性炭电极的电化学性能研究

应用异相沉淀法制备聚三苯胺/活性炭复合材料.SEM及电化学测试表明:聚三苯胺与活性炭复合后,材料的粒径从150 nm左右下降到几十nm,该电极具有良好的倍率性能和循环性能,0.5 C倍率放电容量从88.5mAh/g增至105 mAh/g左右,40 C倍率放电容量约达70 mAh/g左右,1000周循环的容量基本不衰减.     

High capacity silicon/carbon composite anode materials for lithium ion batteries

Silicon/carbon composite materials are prepared by pyrolysis of pitch embedded with graphite and silicon powders. As anode for lithium ion batteries, its initial reversible capacity is 800–900 mAh/g at 0.25 mA/cm² in a voltage range of 0.02/1.5 V vs. Li. The material modification by adding a small amount of CaCO₃ into precursor improves the initial reversibility (η₁=84%) and suppresses the capacity fade upon cycling. A little higher insertion voltage of the composites than commercial CMS anode material improves the cell safety in the high rate charging process.     

二次包覆法制备煤沥青基硅/碳复合物及其锂离子电池性能

本文采用市售纳米硅为硅源,以软化点低、得碳率高、价格便宜的煤沥青作为碳源,通过两步包覆法制备了煤沥青基硅/碳(Si/C/C)复合物,并研究其作为锂离子电池负极材料的电化学性能。 结果表明,所得复合物的粒径在300~350 nm间,Si纳米粒子被C包覆并相互连结成C-Si-C网络结构,其中Si含量为27%的硅/碳复合物(Si/C/C-27%)作为锂电池电极材料表现了良好的储锂性能。 在0.1 A/g的小电流密度下,Si/C/C-27%的放电比容量为1281 mA·h/g;在3 A/g的大电流密度下,其放电比容量仍能保持在582 mA·h/g,表现了良好的倍率性能。Si/C/C-27%在2 A/g的电流密度下经过100次的循环后其比容量保持率为76.61%,表现了良好的循环稳定性。 相比于煤沥青基碳的一次包覆所得的硅/碳复合材料(Si/C),Si/C/C有效提高了Si纳米粒子的导电性并抑制了其在嵌锂和脱锂过程中的体积膨胀。 本文提出的二次包覆的新方法为制备具有优异电化学性能的锂离子电池负极材料提供了新的研究思路。     

Nano-sized lithium manganese oxide dispersed on carbon nanotubes for energy storage applications

Nano-sized lithium manganese oxide (LMO) dispersed on carbon nanotubes (CNT) has been synthesized successfully via a microwave-assisted hydrothermal reaction at 200 °C for 30 min using MnO₂-coated CNT and an aqueous LiOH solution. The initial specific capacity is 99.4 mAh/g at a 1.6 C-rate, and is maintained at 99.1 mAh/g even at a 16 C-rate. The initial specific capacity is also maintained up to the 50th cycle to give 97% capacity retention. The LMO/CNT nanocomposite shows excellent power performance and good structural reversibility as an electrode material in energy storage systems, such as lithium-ion batteries and electrochemical capacitors. This synthetic strategy opens a new avenue for the effective and facile synthesis of lithium transition metal oxide/CNT nanocomposite.     

Preparation of Anode Material for Lithium Ion Battery by Chemical Oxidation

Sincetheoilcrisisinthe60'sand70's,ithasbeenrealizedthatthenaturalresourcesareveryimportantandtheresearchoflithiumsecondarybatterywasthenbegun.Recently,theurgentdemandofmicroelectronicsforsecondarybatterywithhighenergydensityandlightweighthasgreatlystimulatedthedevelopmentoflithiumsecondarybattery.Onlyintheearly90's,didthiskindofbatterybecomecommercialwhenitwasfoundthatgraphitecansubstitUtelithiumorlithiumalloysandsolvetheproblemsofsafetyandcyclelife.However,thesynthesisconditionforgraphiteiscr…     

Facile simultaneous polymerization enabled in-situ confinement of size-tailored GeO2 nanocrystals in continuous S-Doped carbons for lithium storage

GeO₂ is a promising anode material for lithium ion batteries due to its high theoretical capacity (1126 mAh g^?1 for reversibly storing 4.4 Li⁺), and moderately low operating voltage (<1.5 V). Nevertheless, the fabrication of truly durable GeO₂ anode with satisfactory rate capability and cycling stability remains a big challenge because of its inherent low conductivity, and the large volume expansion upon charge-discharge that causes severe capacity fading. In this study, an innovative nanostructure with size-adjustable GeO₂ nanoparticles (16–26 nm) embedded in continuous S-doped carbon (GeO₂/S-doped carbon, GSC) has been successfully fabricated via a facile in-situ simultaneous polymerization method followed by heat treatment. The electrochemical results indicate that the as-prepared GSC composites show high reversible capacity (672.9 mAh g^?1 at 50 mA g^?1), superior rate capability (332.9 mAh g^?1 at 1000 mA g^?1), and long-term cycle life (179 mAh g^?1 after 500 cycles at 1000 mA g^?1) as anode materials for lithium ion batteries. The excellent electrochemical performance of GSC nanocomposites could be ascribed to the homogeneous and continuous S-doped carbon matrix, which provides shortened ion diffusion pathway, increased electrical conductivity, enhanced structural stability, and introduced surface/interface property.     

High performance Si/MgO/graphite composite as the anode for lithium-ion batteries

The Si/MgO/graphite composite was synthesized by high energy ball-milling and evaluated as a durable anode for lithium-ion batteries. EDX mapping indicated that Si was dispersed homogeneously in the MgO matrix. The composite delivered an initial capacity of ~ 700 mAh/g and maintained a capacity of 630 mAh/g after 74 cycles at 0.5 mA/cm²; even at 8 mA/cm² it delivered more than 85% of its capacity. Its volumetric capacity is double that of carbon. The coulombic efficiency climbed from 77% in the first cycle to above 99.5% after 20 cycles, and retained that value.