scholarly journals Synthesis and Characterization of Stable and Binder-Free Electrodes of TiO2Nanofibers for Li-Ion Batteries

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Phontip Tammawat ◽  
Nonglak Meethong
Keyword(s):  
Electron Microscopy ◽  
Electrochemical Impedance ◽  
Coulombic Efficiency ◽  
Electronic Conductivity ◽  
Lithium Ion ◽  
Electrospun Nanofibers ◽  
Average Diameter ◽  
Reversible Capacity ◽  
Electrospinning Technique ◽  
Binder Free

An electrospinning technique was used to fabricate TiO2nanofibers for use as binder-free electrodes for lithium-ion batteries. The as-electrospun nanofibers were calcined at 400–1,000°C and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). SEM and TEM images showed that the fibers have an average diameter of ~100 nm and are composed of nanocrystallites and grains, which grow in size as the calcination temperature increases. The electrochemical properties of the nanofibers were evaluated using galvanostatic cycling and electrochemical impedance spectroscopy. The TiO2nanofibers calcined at 400°C showed higher electronic conductivity, higher discharge capacity, and better cycling performance than the nanofibers calcined at 600, 800, and 1,000°C. The TiO2nanofibers calcined at 400°C delivered an initial reversible capacity of 325 mAh·g−1approaching their theoretical value at 0.1 C rate and over 175 mAh·g−1at 0.3 C rate with limited capacity fading and Coulombic efficiency between 96 and 100%.

scholarly journals Nanocomposite of Si/C Anode Material Prepared by Hybrid Process of High-Energy Mechanical Milling and Carbonization for Li-Ion Secondary Batteries

2018 ◽  
Vol 8 (11) ◽  
pp. 2140 ◽  
Author(s):  
Reddyprakash Maddipatla ◽  
Chadrasekhar Loka ◽  
Woo Choi ◽  
Kee-Sun Lee
Keyword(s):  
Electron Microscopy ◽  
Anode Material ◽  
Mechanical Milling ◽  
Coulombic Efficiency ◽  
Electronic Conductivity ◽  
High Capacity ◽  
Lithium Ion ◽  
High Energy ◽  
Particle Size Reduction ◽  
Milled Powders

Si/C nanocomposite was successfully prepared by a scalable approach through high-energy mechanical milling and carbonization process. The crystalline structure of the milled powders was studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Morphology of the milled powders was investigated by Field-emission scanning electron microscopy (FE-SEM). The effects of milling time on crystalline size, crystal structure and microstructure, and the electrochemical properties of the nanocomposite powders were studied. The nanocomposite showed high reversible capacity of ~1658 mAh/g with an initial cycle coulombic efficiency of ~77.5%. The significant improvement in cyclability and the discharge capacity was mainly ascribed to the silicon particle size reduction and carbon layer formation over silicon for good electronic conductivity. As the prepared nanocomposite Si/C electrode exhibits remarkable electrochemical performance, it is potentially applied as a high capacity anode material in the lithium-ion secondary batteries.

scholarly journals Improved lithium-ion battery anode capacity with a network of easily fabricated spindle-like carbon nanofibers

2016 ◽  
Vol 7 ◽  
pp. 1289-1295 ◽  
Author(s):  
Mengting Liu ◽  
Wenhe Xie ◽  
Lili Gu ◽  
Tianfeng Qin ◽  
Xiaoyi Hou ◽  
...  
Keyword(s):  
Carbon Nanofibers ◽  
Coulombic Efficiency ◽  
High Capacity ◽  
Lithium Ion ◽  
Carbon Matrix ◽  
Reversible Capacity ◽  
Excellent Electrochemical Performance ◽  
Rate Capacity ◽  
Binder Free ◽  
Carbon Network

A novel network of spindle-like carbon nanofibers was fabricated via a simplified synthesis involving electrospinning followed by preoxidation in air and postcarbonization in Ar. Not only was the as-obtained carbon network comprised of beads of spindle-like nanofibers but the cubic MnO phase and N elements were successfully anchored into the amorphous carbon matrix. When directly used as a binder-free anode for lithium-ion batteries, the network showed excellent electrochemical performance with high capacity, good rate capacity and reliable cycling stability. Under a current density of 0.2 A g−1, it delivered a high reversible capacity of 875.5 mAh g−1 after 200 cycles and 1005.5 mAh g−1 after 250 cycles with a significant coulombic efficiency of 99.5%.

Effect of LiCl and non-ionic surfactant on morphology of polystyrene electrospun nanofibers

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Delaram Fallahi ◽  
Mehdi Rafizadeh ◽  
Naser Mohammadi ◽  
Behrooz Vahidi
Keyword(s):  
Electron Microscopy ◽  
Surface Tension ◽  
Electrospun Nanofibers ◽  
Average Diameter ◽  
Ionic Surfactant ◽  
Electrospun Fibers ◽  
Electrospinning Technique ◽  
Solution Surface ◽  
Solution Conductivity ◽  
Scanning Electron

AbstractPolystyrene fibers were produced by the electrospinning technique. The effects of solution conductivity, surface tension and concentration on morphology and average diameter of electrospun fibers were investigated by scanning electron microscopy (SEM). Solutions of 12, 10, 8, 6% (w/v) polystyrene in dimethylformamide were prepared. Lithium Chloride and a non-ionic surfactant were used to change the conductivity and surface tension of the solutions, respectively. The results indicate that increasing the solution conductivity eliminates the bead formation and increases the fiber diameters. By addition of salt, fine and consistent fibers could be produced from electrospinning of 8% (w/v) PS/DMF solution. Adding 0.1% surfactant reduces the solution surface tension and results in smaller beads and higher fiber diameters. By increasing the amount of surfactant to 0.3%, big beads and thinner fibers are produced.

Synthesis and Electrochemical Performance of Tin-Copper Nanocomposites as a Superior Anode for Lithium-Ion Batteries

2016 ◽  
Vol 852 ◽  
pp. 894-900
Author(s):  
Tian Chen ◽  
Jin Pan ◽  
Ren Cheng Shen ◽  
Jian Qiu Deng ◽  
Qing Rong Yao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrochemical Impedance ◽  
Coulombic Efficiency ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Cycling Performance ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
High Resolution Tem

The Sn–Cu nanocomposites composing of Sn, Cu6Sn5, Cu3Sn and SnO2 are synthesized by a facile precipitation method. Their morphologies and structures are characterized using X-ray diffraction (XRD) technique, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution TEM. The electrochemical properties are investigated by charge–discharge testing, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods. The sample with a Sn/Cu ratio of 5:3 delivers good cycling stability. The discharge specific capacity is 447.5 mAhg-1 after 70 cycles at a current density of 100 mAg-1 and the coulombic efficiency is beyond 95%. The superior rate and cycling performance of Sn–Cu nanocomposites are also demonstrated, which may be rooted in their nanostructure and phase composition.

scholarly journals PEDOT-Coated Red Phosphorus Nanosphere Anodes for Pseudocapacitive Potassium-Ion Storage

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1732
Author(s):  
Dan Zhao ◽  
Qian Zhao ◽  
Zhenyu Wang ◽  
Lan Feng ◽  
Jinying Zhang ◽  
...  
Keyword(s):  
Surface Engineering ◽  
Electronic Conductivity ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Average Diameter ◽  
Potassium Ion ◽  
Red Phosphorus ◽  
Fast Charging ◽  
Potential Alternative ◽  
High Theoretical Capacity

Potassium-ion batteries (KIBs) have come up as a potential alternative to lithium-ion batteries due to abundant potassium storage in the crust. Red phosphorus is a promising anode material for KIBs with abundant resources and high theoretical capacity. Nevertheless, large volume expansion, low electronic conductivity, and limited K+ charging speed in red phosphorus upon cycling have severely hindered the development of red phosphorus-based anodes. To obtain improved conductivity and structural stability, surface engineering of red phosphorus is required. Poly(3,4-ethylenedioxythiophene) (PEDOT)-coated red phosphorus nanospheres (RPNP@PEDOT) with an average diameter of 60 nm were synthesized via a facile solution-phase approach. PEDOT can relieve the volume change of red phosphorus and promote electron/ion transportation during charge−discharge cycles, which is partially corroborated by our DFT calculations. A specific capacity of 402 mAh g−1 at 0.1 A g−1 after 40 cycles, and a specific capacity of 302 mAh g−1 at 0.5 A g−1 after 275 cycles, were achieved by RPNP@PEDOT anode with a high pseudocapacitive contribution of 62%. The surface–interface engineering for the organic–inorganic composite of RPNP@PEDOT provides a novel perspective for broad applications of red phosphorus-based KIBs in fast charging occasions.

Electrochemical Performance Optimization of Li2NixFe1−xSiO4 Cathode Materials for Lithium-Ion Batteries

2017 ◽  
Vol 14 (2) ◽  
Author(s):  
Atef Y. Shenouda ◽  
M. M. S. Sanad
Keyword(s):  
Performance Optimization ◽  
Electrochemical Impedance ◽  
Coulombic Efficiency ◽  
Sol Gel ◽  
Lithium Ion ◽  
Electrochemical Impedance Spectra ◽  
Cell Parameters ◽  
Sol Gel Process ◽  
Eis Measurements ◽  
And Function

Li2NixFe1−xSiO4 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) samples were prepared by sol–gel process. The crystal structure of prepared samples of Li2NixFe1−xSiO4 was characterized by XRD. The different crystallographic parameters such as crystallite size and lattice cell parameters have been calculated. Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) investigations were carried out explaining the morphology and function groups of the synthesized samples. Furthermore, electrochemical impedance spectra (EIS) measurements are applied. The obtained results indicated that the highest conductivity is achieved for Li2Ni0.4Fe0.6SiO4 electrode compound. It was observed that Li/Li2Ni0.4Fe0.6SiO4 battery has initial discharge capacity of 164 mAh g−1 at 0.1 C rate. The cycle life performance of all Li2NixFe1−xSiO4 batteries was ranged between 100 and 156 mAh g−1 with coulombic efficiency range between 70.9% and 93.9%.

scholarly journals Commercial Cokes and Graphites as Anode Materials for Lithium - Ion Cells

1997 ◽  
Vol 496 ◽  
Author(s):  
David J. Derwin ◽  
Kim Kinoshita ◽  
Tri D. Tran ◽  
Peter Zaleski
Keyword(s):  
Electron Microscopy ◽  
Ethylene Carbonate ◽  
Average Particle Size ◽  
Chemical Properties ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Bet Surface Area ◽  
Average Particle ◽  
Electrochemical Characteristics ◽  
Wide Range

AbstractSeveral types of carbonaceous materials from Superior Graphite Co. were investigated for lithium ion intercalation. These commercially available cokes, graphitized cokes and graphites have a wide range of physical and chemical properties. The coke materials were investigated in propylene carbonate based electrolytes and the graphitic materials were studied in ethylene carbonate / dimethyl solutions to prevent exfoliation. The reversible capacities of disordered cokes are below 230 mAh / g and those for many highly ordered synthetic (artificial) and natural graphites approached 372 mAh / g (LiC6). The irreversible capacity losses vary between 15 to as much as 200 % of reversible capacities for various types of carbon. Heat treated cokes with the average particle size of 10 microns showed marked improvements in reversible capacity for lithium intercalation. The electrochemical characteristics are correlated with data obtained from scanning electron microscopy (SEM), high resolution transmission electron microscopy (TAM), X - ray diffraction (XRD) and BET surface area analysis. The electrochemical performance, availability, cost and manufacturability of these commercial carbons will be discussed.

Growth Mechanism and Electrochemical Properties of Porous Hollow Tin Dioxide Nanospheres

NANO ◽  
2015 ◽  
Vol 10 (06) ◽  
pp. 1550087 ◽  
Author(s):  
Youwen Yang ◽  
Dongming Ma ◽  
Ting Cheng ◽  
Yuanhao Gao ◽  
Guanghai Li
Keyword(s):  
Growth Mechanism ◽  
Tin Dioxide ◽  
Ostwald Ripening ◽  
Lithium Ion ◽  
Average Diameter ◽  
Reversible Capacity ◽  
Cycling Performance ◽  
Experimental Conditions ◽  
Electrochemical Tests ◽  
Hydrolysis Method

Porous hollow SnO 2 nanospheres were prepared by means of enforced Sn 2+ hydrolysis method under hydrochloric acid medium. These hollow nanospheres with an average diameter of 220nm had a very thin shell thickness of about 40nm and were surrounded by elongated octahedral-like nanoparticles with the apex oriented outside. The experimental conditions, such as HCl content, reaction temperature and time directly dominated the morphology, structure and crystallinity of the obtained samples. A pre-oxidation-nucleation-growth mechanism and inside-out Ostwald-ripening method was proposed on the basis of the previous research and time-dependent experiments. Electrochemical tests showed that the porous hollow SnO 2 nanospheres exhibited improved cycling performance for anode materials of lithium-ion batteries, which retained a high reversible capacity of 540.0mAhg-1, and stable cyclic retention at 120th cycle.

PROPERTIES OF ALL-SOLID-STATE LITHIUM-ION RECHARGEABLE BATTERIES DEPOSITED BY RF MAGNETRON SPUTTERING

2013 ◽  
Vol 27 (22) ◽  
pp. 1350156 ◽  
Author(s):  
R. J. ZHU ◽  
Y. REN ◽  
L. Q. GENG ◽  
T. CHEN ◽  
L. X. LI ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Solid State ◽  
Magnetron Sputtering ◽  
Coulombic Efficiency ◽  
Electronic Conductivity ◽  
Lithium Ion ◽  
Rf Magnetron Sputtering ◽  
Rechargeable Batteries ◽  
Voltage Range

Amorphous V 2 O 5, LiPON and Li 2 Mn 2 O 4 thin films were fabricated by RF magnetron sputtering methods and the morphology of thin films were characterized by scanning electron microscopy. Then with these three materials deposited as the anode, solid electrolyte, cathode, and vanadium as current collector, a rocking-chair type of all-solid-state thin-film-type Lithium-ion rechargeable battery was prepared by using the same sputtering parameters on stainless steel substrates. Electrochemical studies show that the thin film battery has a good charge–discharge characteristic in the voltage range of 0.3–3.5 V, and after 30 cycles the cell performance turned to become stabilized with the charge capacity of 9 μAh/cm2, and capacity loss of single-cycle of about 0.2%. At the same time, due to electronic conductivity of the electrolyte film, self-discharge may exist, resulting in approximately 96.6% Coulombic efficiency.

Synthesis and Electrochemical Performance of SnO2/Graphene Hybrid Anode for Lithium Ion Batteries

2013 ◽  
Vol 1540 ◽  
Author(s):  
Chia-Yi Lin ◽  
Chien-Te Hsieh ◽  
Ruey-Shin Juang
Keyword(s):  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Anode Material ◽  
High Performance ◽  
Coulombic Efficiency ◽  
Rate Capability ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Cycling Performance ◽  
Homogeneous Distribution

ABSTRACTAn efficient microwave-assisted polyol (MP) approach is report to prepare SnO2/graphene hybrid as an anode material for lithium ion batteries. The key factor to this MP method is to start with uniform graphene oxide (GO) suspension, in which a large amount of surface oxygenate groups ensures homogeneous distribution of the SnO2 nanoparticles onto the GO sheets under the microwave irradiation. The period for the microwave heating only takes 10 min. The obtained SnO2/graphene hybrid anode possesses a reversible capacity of 967 mAh g-1 at 0.1 C and a high Coulombic efficiency of 80.5% at the first cycle. The cycling performance and the rate capability of the hybrid anode are enhanced in comparison with that of the bare graphene anode. This improvement of electrochemical performance can be attributed to the formation of a 3-dimensional framework. Accordingly, this study provides an economical MP route for the fabrication of SnO2/graphene hybrid as an anode material for high-performance Li-ion batteries.

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