Three-dimensional nanocarbon and the electrochemistry of nanocarbon/tin oxide for lithium ion batteries

In this work, the potential of using coconut shell, which is very cheap and readily available, for the production of graphitic nanocarbon three-dimensional networks is investigated. The three-dimensional carbon has been produced via the wet-impregnation of coconut shell powder with a transition metal catalyst. The novel process employed offers low costs and environmental advantages, with biological waste used in place of carbonaceous precursor as the feedstock. Nanocarbon/tin oxide composites were prepared via wet-impregnation and the solvothermal method, using tin chloride solution with the activated nanocarbon. The electrochemical performances of the three-dimensional nanocarbon doped with tin oxide and of activated nanocarbon alone as anode materials were investigated in rechargeable lithium ion batteries. One composite made by using the solvothermal method shows stable cyclic retention up to 100 cycles and delivers a high reversible capacity of about 405 mAh g⁻¹.

     

Enhancement of thin film tin oxide negative electrodes for lithium batteries

Thin films of pure SnO₂, of the Sn/Li₂O layered structure, and of Sn/Li₂O were fabricated by sputtering method, while a `lithium-reacted tin oxide thin film' was assembled by the evaporation of lithium metal onto a SnO₂ thin film. Film structure and charge/discharge characteristics were compared. The lithium-reacted tin oxide thin film, the Sn/Li₂O layered structure, and the Sn/Li₂O co-sputtered thin films did not show any irreversible side reactions of forming Li₂O and metallic Sn near 0.8 V vs Li/Li⁺. The initial charge retention of the Sn/Li₂O layered structure and Sn/Li₂O co-sputtered thin films was about 50% and a similar value was found for the lithium-reacted tin oxide thin film (more than 60%). Sn/Li₂O layered structure and Sn/Li₂O co-sputtered thin films showed better cycling behavior over 500 cycles than the pure SnO₂ and lithium-reacted tin oxide thin film in the cut-off range from 1.2 to 0 V vs Li/Li⁺.     

Inside the failure mechanism of tin oxide as anode for sodium ion batteries

Journal of Solid State Electrochemistry - The conversion-alloying compounds have been identified as promising anode materials for sodium ion batteries (SIBs). One of them, SnO2, with an enormous...     

Anodes for lithium batteries: tin revisited

Pure tin, without the addition of conducting diluents or binders, has been evaluated as an anode in lithium cells. Capacities approaching 600 mAh/g are maintained for over 10 deep cycles, before falling off, indicating the inherent reversibility of the tin anode. These are comparable to those reported for Cu₆Sn₅ and considerably higher than for deposited tin films. The tin grain size was determined and found to decrease with cycling from over 400 to below 100 nm over 10 cycles. The cell impedance increases significantly after 10 cycles, consistent with the observed loss of capacity on extended cycling.     

Surface modified TiO2/reduced graphite oxide nanocomposite anodes for lithium ion batteries

Journal of Solid State Electrochemistry - Anatase TiO2 nanoparticles with an average crystallite size of ~ 20 nm are synthesized through a sol-gel method. A composite anode for...     

锂离子电池锡基复合氧化物负极材料的研究

采用共沉淀法制备了SnSbO2.5和SnGeO3两种锡基复合氧化物粉末.XRD分析表明,这两种锡基复合氧化物的共同特点是在27°～28°处有波峰,属无定型结构.将其分别作为锂离子电池负极材料的活性物质,利用恒电流电池测试仪研究它们的电化学性能.实验表明,这两种锡基复合氧化物都有较高的电化学容量,SnSbO2.5的可逆容量为1200mA·h/g,SnGeO3的可逆容量为750mA·h/g.这两种锡基复合氧化物的电化学容量远高于碳材料(石墨的理论容量为372mA·h/g),因此,这两种锡基复合氧化物可以作为锂离子电池负极材料的候选材料.     

Synthesis of lithium metal silicates for lithium ion batteries

Synthesis strategies, nanostructures, and different electrochemical performances are prominent features of rechargeable batteries. Three types Li₂MSiO₄ cathode metarials for lithium ion batteries:Li₂FeSiO₄, Li₂MnSiO₄, and Li₂CoSiO₄ are scientifically discussed, and the comprehensive summaries and evaluations are given in this review.     

Direct electrochemistry and electrocatalysis of hemoglobin on a gold ion implantation-modified indium tin oxide electrode

In this paper, a gold nanoparticle-modified indium tin oxide electrode (Au/ITO) was prepared without the use of any cross-linker or stabilizer reagent. The prepared Au/ITO was used as a new platform to achieve the direct electron transfer between Hb and the modified electrode. The proposed electrode exhibited a pair of well-defined redox peaks with a formal potential of ?0.073 V (vs. Ag/AgCl). The immobilized Hb showed excellent electrocatalytic activity toward H₂O₂ and the electrocatalytic current values were linear with the increasing concentration of H₂O₂ ranging from 1.0?×?10^?6?M to 7.0?×?10^?4?M. The detection limit was 2.0?×?10^?7?M (S/N?=?3) and the Michaelis–Menten constant was calculated to be 0.2 mM. The proposed electrode also showed high selectivity, long-term stability, and good reproducibility.     

Formation of SnS nanoflowers for lithium ion batteries

SnS nanoflowers containing hierarchically organized nanosheet subunits were synthesized using a simple solution route, and they function as lithium ion battery anodes that maintain high capacities and coulombic efficiencies over 30 cycles.     

Core-shell structured electrode materials for lithium ion batteries

Recent progress in studies of several types of core-shell structured electrode materials, including TiO₂/C, Si/C, Si/SiO _x , LiCoO₂/C, and LiFePO₄/C nanocomposites, including details of their preparation and their electrochemical performance is briefly reviewed. Results clearly show that the coating shell can effectively prevent the aggregation of the nanosized cores, which are the electrochemically active materials. In addition, the diffusion coefficients of lithium ions can be increased, and the reversibility of lithium intercalation and deintercalation is improved. As a result, the cycling behavior is greatly improved. The reviewed results suggest that core-shell nanocomposites are a good starting point for further development of new promising electrode materials.

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CoO octahedral nanocages for high-performance lithium ion batteries

Pure-phase CoO octahedral nanocages were successfully fabricated by a novel simple method. The coordination etching agents play key roles in the formation of these non-spherical hollow structures. When tested as anode materials in lithium ion batteries (LIBs), these nanocages showed excellent cycling performance, good rate capability and enhanced lithium storage capacity.     

Synthesis and electrochemistry of polymer based electrolytes for lithium batteries

An overview is presented on the development of improved polymer based electrolytes during the past years. The emphasis lies on new approaches regarding chemical concepts that achieve a higher total conductivity and lithium transference number as well as an increased electrochemical, mechanical and thermal stability. With respect to the polymer chemistry, the focus is laid on siloxane and phosphazene derived systems. Topics are the chemical modification of the polymeric, cyclic and low molecular derivates of these systems, the formation of stable membranes from these by suitable cross-linking strategies and an extensive electrochemical characterization in corresponding lithium cells. Recent trends towards composite and hybrid materials are illustrated with examples and newly developed hybrid electrolytes. A particular chance for improvements comes from the design and use of stable small molecular additives in combination with optimized and electrochemically stable polymer networks. Special compounds are introduced which may act themselves as novel solvents with increased electrochemical stabilities. The relevance of chosen lithium salts for polymer electrolytes is discussed, too, and a new family of pyrazolide anions is introduced. In all cases, the electrochemical performance has been characterized by standard experimental techniques.     

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.     

Hierarchically ordered porous nickel oxide array film with enhanced electrochemical properties for lithium ion batteries

Hierarchically ordered porous nickel oxide array film was prepared by electrodeposition through monolayer polystyrene spheres template. The as-prepared film had a highly porous structure of interconnected macrobowls array possessing nanopores. As anode material for lithium ion batteries, the porous array NiO film exhibited weaker polarization, higher coulombic efficiency and better cycling performance in comparison with the dense NiO film. After 50 cycles, the discharge capacity of porous array NiO film was 518 mAh g^? 1 at 1 C rate, higher than that of the dense NiO film (287 mAh g^? 1). The enhancement of the electrochemical properties was due to the unique hierarchical porous architecture, which provided fast ion/electron transfer and alleviated the structure degradation during the cycling process.     

Net-like SnS/carbon nanocomposite film anode material for lithium ion batteries

SnS particles with sizes of 5.0–6.5 nm were prepared by a facile method. Resorcinol–formaldehyde sol with addition of the as-prepared SnS nanoparticles was spin-coated on a copper foil to prepare net-like SnS/C composite thin-film electrode for lithium ion batteries after carbonization at 650 °C. The SnS/C nanocomposite thin-film electrode showed preferable first coulombic efficiency and excellent cycling stability. The discharge and charge capacities were respectively 542.3 and 531.3 mAh/g after 40 cycles. The attractive electrochemical performances were mainly ascribed to the ultra fine particle, which showed no evident aggregation in high-resolution TEM image, and the effects of 3-dimensional net-like carbon structure, which uniformly surrounded the SnS nanoparticles to guarantee the contact, acted as a buffer matrix to alleviate the volume expansion of Li–Sn alloy and provided enough paths for electrolyte to reach SnS active material during discharge–charge process.     

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.     

The development of lithium ion secondary batteries

Lithium ion secondary batteries (LIBs) were successfully developed as battery systems with high volumetric and gravimetric energy densities, which were inherited from lithium secondary batteries (LSBs) with metallic lithium anodes. LSBs have several drawbacks, however, including poor cyclability and quick-charge rejection. The cell reaction in LIB is merely a topochemical one, namely the migration of lithium ions between positive and negative electroces. No chemical changes were observed in the two electrodes or in the electrolytes. This results in little chemical transformation of the active electrode materials and electrolytes, and thus, LIBs can overcome the weaknesses of LSBs; for example, LIBs show excellent cyclability and quick-charge acceptance. Many difficulties, however, were encountered during the course of development, including capacity fade during cycling and safety issues. This article is the story of the development of LIBs and it describes how the difficulties were surmounted.     

The advance of fiber-shaped lithium ion batteries

With the development of wearable devices, much attention has been paid to the energy supply for these devices. Traditional batteries are not suitable for wearable devices due to their rigidity and high-density. Meanwhile, flexible and lightweight planar batteries cannot be fitted to the fabric well and have poor permeability, which lower the degree of the wearing comfort of the fabric. Therefore, the fiber-shaped lithium ion battery (LIB) becomes one of the best energy storage devices which can solve all the problems mentioned above because of its light-weight, flexibility, weavability and stretchability. However, the capacity of fiber-shaped LIBs is always lower than the capacity of planar batteries because of the low loading of active materials, and the circuit connection will be very complicated in further weaving. In this review article, we introduce the development of the fiber-shaped LIB, summarize the main challenges and finally point out the future direction of this field.     

Modification of LiCoO2 through rough coating with lithium lanthanum zirconium tantalum oxide for high-voltage performance in lithium ion batteries

Journal of Solid State Electrochemistry - In this study, the spray-drying technique was used to apply a 0.5 at%, 1 at%, and 1.25 at% of lithium lanthanum zirconium tantalum oxide...