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%.     

Hydrothermal synthesis of rod-like CoMoO4 and its excellent properties for the anode of lithium-ion batteries

CoMoO₄ has attracted extensive interest as an anode for lithium-ion batteries due to its high theoretical capacity and low cost. Nevertheless, achieving controlled synthesis of CoMoO₄ with definite morphology by simply adjusting a certain synthesis condition is a very meaningful topic. Here, rod-like CoMoO₄ formed by lamellar stacking was successfully synthesized through the control pH value of one-step hydrothermal route, and its excellent electrochemical performance was investigated. The rod-like CoMoO₄ prepared at 190°C and pH = 7 has a high initial discharge capacity of 1,482.8 mAh/g at 200 mA/g. The discharge capacity of 1,041 mAh/g was maintained after 500 cycles, and the capacity retention was 70.2%. The improved electrochemical performance of rod-like CoMoO₄ can be attributed to the rod structures, which could shorten ion diffusion and electronic conduction pathway, provide more efficient charge storage sites, and alleviate the volume changes during Li + intercalation/deintercalation.     

A ternary phased SnO2-Fe2O3/SWCNTs nanocomposite as a high performance anode material for lithium ion batteries

A new SnO_2-Fe_2O_3/SWCNTs(single-walled carbon nanotubes) ternary nanocomposite was first synthesized by a facile hydrothermal approach.SnO_2 and Fe_2O_3 nanoparticles(NPs) were homogeneously located on the surface of SWCNTs,as confirmed by X-ray diffraction(XRD),transmission electron microscope(TEM) and energy dispersive X-ray spectroscopy(EDX).Due to the synergistic effect of different components,the as synthesized SnO_2-Fe_2O_3/SWCNTs composite as an anode material for lithium-ion batteries exhibited excellent electrochemical performance with a high capacity of 692 mAh·g~(-1) which could be maintained after 50 cycles at 200 mA·g~(-1).Even at a high rate of2000 mA·g~(-1),the capacity was still remained at 656 mAh·g~(-1).     

Nano-sized carboxylates as anode materials for rechargeable lithium-ion batteries

Nano-sized caiboxylales Na2C7H3NO4 and Na2C6H2N2O4 were prepared and investigated as anode materials for lithium-ion batteries.Both carboxylates exhibit high reversible capacities around 190 mAh/g above a cut-off voltage of 0.8 V vs.Li＋/Li.potentially improving the safety of the batteries.In addition,good rate performance and long cycle life of these carboxylates make them promising candidates as anode materials for lithium-ion batteries.     

Facile synthesized Cu-SnO2 anode materials with three-dimensional metal cluster conducting architecture for high performance lithium-ion batteries

A novel Cu-SnO₂ anode material derived from Cu₆Sn₅ alloy, retaining high conductivity of Cu and high theoretical capacity of SnO₂ with a facile synthesizing process by oxidation and reduction method. The novel Cu structure penetrates in the composite particles inducing high conductivity and spaceconfined SnO₂, which restrict the pulverization of SnO₂ during lithiation/delithiation process.     

Superior cycle performance of Sn@C/graphene nanocomposite as an anode material for lithium-ion batteries

A novel anode material for lithium-ion batteries, tin nanoparticles coated with carbon embedded in graphene (Sn@C/graphene), was fabricated by hydrothermal synthesis and subsequent annealing. The structure and morphology of the nanocomposite were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The size of the Sn@C nanoparticles is about 50-200 nm. The reversible specific capacity of the nanocomposite is ∼662 mAh g⁻¹ at a specific current of 100 mA g⁻¹ after 100 cycles, even ∼417 mAh g⁻¹ at the high current of 1000 mA g⁻¹. These results indicate that Sn@C/graphene possesses superior cycle performance and high rate capability. The enhanced electrochemical performances can be ascribed to the characteristic structure of the nanocomposite with both of the graphene and carbon shells, which buffer the volume change of the metallic tin and prevent the detachment and agglomeration of pulverized tin.     

Hexagonal hollow mesoporous TiO2/carbon composite as an advanced anode material for lithium-ion batteries

Journal of Solid State Electrochemistry - Exploring the fast-charge anodes is crucial to meet the needs of lithium-ion battery (LIB) markets. Here, a hollow hexagonal mesoporous TiO2/carbon...     

SnO2 sheet/graphite composite as anode material with improved electrochemical performance for lithium-ion batteries

The SnO₂ sheet/graphite composite was synthesized by a hydrothermal method for high-capacity lithium storage. The microstructures of products were characterized by XRD and FE-SEM. The electrochemical performance of SnO₂ sheet/graphite composite was measured by galvanostatic charge/discharge cycling and EIS. The first discharge and charge capacities are 1,072 and 735 mAh g^?1 with coulombic efficiency of 68.6 %. After 40 cycles, the reversible discharge capacity is still maintained at 477 mAh g^?1. The results show that the SnO₂ sheet/graphite composite displays superior Li-battery performance with large reversible capacity and good cyclic performance.     

SnO2 hollow nanospheres assembled by single layer nanocrystals as anode material for high performance Li ion batteries

SnO₂ hollow nanospheres were successfully synthesized via a facile one-step solvothermal method.Characterizations show that the as-prepared SnO₂ spheres are of hollow structure with a diameter at around 50 nm,and especially,the shell of the spheres is assembled by single layer SnO₂ nanocrystals.The surface area of the material reaches up to 202.5 m²/g.As an anode material for Li ion batteries,the sample exhibited improved electrochemical performance compared with commercial SnO₂ particles.After cycled at high current rate of 0.5 C,1 C and 0.5 C for 20 cycles,respectively,the electrode can maintain a capacity of 509 mAh/g.The suitable shell thickness/diameter ratio endows the good structural stability of the material during cycling,which promises the excellent cycling performance of the electrode.The large surface area and the ultra thin shell ensure the high rate performance of the material.     

原子尺度锂离子电池电极材料的近平衡结构

锂离子电池充放电过程中电极材料的结构变化与材料的电化学反应机理和性能密切相关.通过在原子尺度上直接观察脱/嵌锂前后电极材料的近平衡微观结构,有助于从更深层次认识电极反应机理和性能演化规律,对于全面理解材料的电化学行为以及改善锂离子电池性能具有重要的指导意义.本文详述了球差校正扫描透射成像技术在研究电极材料表界面结构及反应机理方面的进展,探讨了未来建立电极材料原子尺度结构与性能相关联可能的研究方向.     

Porous V2O5-SnO2/CNTs composites as high performance cathode materials for lithium-ion batteries

Vanadium pentoxide (V₂O₅) exhibits high theoretical capacities when used as a cathode in lithium ion batteries (LIBs), but its application is limited by its structural instability as well as its low lithium and electronic conductivities. A porous composite of V₂O₅-SnO₂/carbon nanotubes (CNTs) was prepared by a hydrothermal method and followed by thermal treatment. The small particles of V₂O₅, their porous structure and the coexistence of SnO₂ and CNTs can all facilitate the diffusion rates of the electrons and lithium ions. Electrochemical impedance spectra indicated higher ionic and electric conductivities, as compared to commercial V₂O₅. The V₂O₅-SnO₂/CNTs composite gave a reversible discharge capacity of 198 mAh·g^?1 at the voltage range of 2.05–4.0 V, measured at a current rate of 200 mA·g^?1, while that of the commercial V₂O₅ was only 88 mAh·g^?1, demonstrating that the porous V₂O₅-SnO₂/CNTs composite is a promising candidate for high-performance lithium secondary batteries.     

具有类混凝土结构的 SiOx-C锂离子电池复合材料的制备

采用一种简单的方法制备具有类钢筋混凝土结构的Si-O-C负极材料,其中碳纳米管(carbon nanotubes,CNTs)如同钢筋一般嵌入材料中以提供应力支撑,硅原子被原子级分散的碳和氧原子均匀包裹,最后通过化学气相沉积镀上最外层的碳层,进一步抑制材料的体积变化。基于此独特的结构设计制备的CNTs/SiO_x-C/C负极表现出优异的电化学性能,其在0.5 A·g^-1的电流密度下循环970圈后容量保留率为80%。     

具有类混凝土结构的SiOx-C锂离子电池复合材料的制备

采用一种简单的方法制备具有类钢筋混凝土结构的Si-O-C负极材料,其中碳纳米管（carbon nanotubes,CNTs）如同钢筋一般嵌入材料中以提供应力支撑,硅原子被原子级分散的碳和氧原子均匀包裹,最后通过化学气相沉积镀上最外层的碳层,进一步抑制材料的体积变化。基于此独特的结构设计制备的CNTs/SiO_x-C/C负极表现出优异的电化学性能,其在0.5 A·g^-1的电流密度下循环970圈后容量保留率为80%。     

SnO_2/corncob-derived activated carbon nanohybrid as an anode material for lithium-ion batteries

A facile synthesis of Sn O2/corncob-derived activated carbon(CAC) composite was proposed,and the CAC used here has high specific surface area(over 3000 m2/g) and ample oxygen-containing functional groups.The microstructures and morphology as well as electrochemical performance of the Sn O2/CAC composites were investigated by X-ray diffraction,scanning electron microscopy,transmission electron microscopy and relevant electrochemical characterization. The results show that the mass ratios of Sn O2 to CAC have a significant effect on the structures and properties of the composites. The sample with 34% Sn O2 delivered a capacity of 879.8 m Ah/g in the first reversible cycle and maintained at 634.0 m Ah/g(72.1% retention of the initial reversible capacity) after 100 cycles at a current density of 200 m A/g. After 60 cycles at different specific currents from 200 to 2000 m A/g,the reversible specific capacity was still maintained at 632.8 m Ah/g at a current density of 200 m A/g. These results indicate that SnO 2/CAC can be a desirable alternative anode material for lithium ion batteries.     

Cerium vanadate/carbon nanotube hybrid composite nanostructures as a high-performance anode material for lithium-ion batteries

The pristine CeVO4 and CeVO4/CNT hybrid composite nanostructured samples were facilely synthesized using a simple silicone oil-bath method.From the X-ray diffra...     

Mesoporous carbon material as cathode for high performance lithium-ion capacitor

The mesoporous carbon material with large pore volume and high surface area by a simple situ MgO template method is synthesized, which is utilized as cathode to assemble a high performance lithium ion capacitor.     

Hierarchically structured MoO2/dopamine-derived carbon spheres as intercalation electrodes for lithium-ion batteries

A hydrogen peroxide initiated sol-gel process involving molybdenum transformation in the presence of dopamine (Dopa) hydrochloride excess produced the metastable precipitate composed of polydopamine (PDopa) spheres coated with Dopa preintercalated molybdenum oxide, (Dopa)_xMoO_y@PDopa. The hydrothermal treatment (HT) of the (Dopa)_xMoO_y@PDopa precursor resulted in the simultaneous carbonization of Dopa and molybdenum reduction generating MoO₂ nanoplatelets distributed and confined on the surface of the Dopa-derived carbon matrix (HT-MoO₂/C). The consecutive annealing (An) of the HT-MoO₂/C sample at 600 °C under Ar atmosphere led to the formation of MoO₂ with increased Mo oxidation state and improved structural stability (AnHT-MoO₂/C). Annealing had also further facilitated interaction between the molybdenum-derived and Dopa-derived components resulting in the modification of the carbon matrix confirmed by Raman spectroscopy. Morphology of both materials is best described as Dopa-derived carbon spheres decorated with MoO₂ nanoplatelets. These integrated metal oxide and carbon structures were tested as electrodes for lithium-ion batteries in the potential window that corresponds to the intercalation mechanism of charge storage. The AnHT-MoO₂/C electrode showed enhanced electrochemical activity, with an initial specific discharge capacity of 260 mAh/g and capacity retention of 67% after 50 cycles, compared to the HT-MoO₂/C electrode which exhibited an initial specific discharge capacity of 235 mAh g^?1 and capacity retention of 47% after 50 cycles. The rate capability experiments revealed that the capacity of 93 mAh/g and 120 mAh/g was delivered by the HT-MoO₂/C and AnHT-MoO₂/C electrodes, respectively, when the current density was increased to 100 mA/g. The improved specific capacity, electrochemical stability, and rate capability achieved after annealing were attributed to higher crystallinity of MoO₂, increased oxidation state of Mo, and formation of the tighter MoO₂/carbon contact accompanied by the annealing assisted interaction between MoO₂ and Dopa-derived carbon.     

Binder-free carbon-coated nanocotton transition metal oxides integrated anodes by laser surface ablation for lithium-ion batteries

In this paper, an efficient laser surface ablation strategy for producing binder-free carbon-coated nanocotton CoO-Co integrated anode is reported. The fabrication process introduces in-situ growing nanocotton-like CoO on the surface of Co foil via ablating with a nanosecond laser. After that, coated with dopamine as carbon source, the CoO-Co composite foil is heated in Argon atmosphere to form a CoO@C-Co foil as an anode of LIB. The laser surface ablation exhibits high fabrication speed (~10 minutes) and significantly reduces the processing time. The obtained binder-free CoO@C-Co integrated anode shows a unique cotton-like villous structure with large specific surface area and an active material/current collector integrated architecture, which provides a stabilized rapid electronic conduction path. When tested as an anode for LIBs, the CoO@C-Co integrated anode possesses superior performance: First discharge capacity of 1301.5 mAh g⁻¹ is achieved at a current density of 0.1 A g⁻¹. Also at a high current density of 1.5 A g⁻¹, the second discharge capacity of 791.7 mAh g⁻¹ is achieved. After 800 cycles, reversible capacities of 799.8 mAh g⁻¹ can still be achieved with an average coulombic efficiency of nearly 100%. In addition, this strategy is suitable for the production of other carbon coated transition metal oxides integrated anodes, such as NiO@C-Ni, Fe₂O₃/Fe₃O₄@C-Fe, and CuO/Cu₂O@C-Cu integrated anodes.