| 1. |
- Amaraweera, Thng, et al.
(författare)
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Development of Li(Ni1/3Mn1/3Co1/3-x Na (x) )O-2 cathode materials by synthesizing with glycine nitrate combustion technique for Li-ion rechargeable batteries
- 2017
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Ingår i: Ionics. - : Springer Science and Business Media LLC. - 0947-7047 .- 1862-0760. ; 23:11, s. 3001-3011
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Tidskriftsartikel (refereegranskat)abstract
- Glycine nitrate combustion technique was investigated for synthesizing Li(Ni1/3Mn1/3Co1/3-x Na (x) )O-2, x = 0-0.11 based transition metal oxide cathode materials for the rechargeable Li-ion battery (LIB) under this study. X-ray diffraction and scanning electron microscopy analysis showed that the synthesized powder samples were well crystalline rather spherical secondary particles. These secondary particles were composed of softly agglomerated nano-scale primary particles. The room temperature electrical conductivity of these Na-doped materials was significantly higher than that of the base material (2.60 x 10(-7) S/cm). Among them, the x = 0.04 material reported the highest electrical conductivity of 1.02 x 10(-03) S cm(-1). The half-cell assembled with cathode fabricated from Li(Ni1/3Mn1/3Co1/3)O-2 base material showed an initial discharge capacity of 187 mA h(-1) g(-1) with 25 mA h(-1) g(-1) irreversible capacity loss and 88.47% columbic efficiency at C/5 rate with a cut-off voltage of 2.5-4.6 V at 25 A degrees C. The electrochemical behavior of the x = 0.04 cathode showed a comparable initial discharge capacity as of the base material but with improved capacity retention.
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| 2. |
- Amaraweera, T. H. N. G., et al.
(författare)
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Surface modification of natural vein graphite for the anode application in Li-ion rechargeable batteries
- 2018
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Ingår i: Ionics. - : Springer Science and Business Media LLC. - 0947-7047 .- 1862-0760. ; 24:11, s. 3423-3429
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Tidskriftsartikel (refereegranskat)abstract
- Natural vein graphite with high purity and crystallinity is seldom used as anode material in lithium-ion rechargeable batteries (LIB) due to impurities and inherent surface structure. This study focuses on improving the surface properties of purified natural vein graphite surface by employing mild chemical oxidation. Needle-platy graphite sample with initial average carbon percentage of 99.83% was improved to 99.98% after treatment with 5 vol.% HCl. Surface modification of purified graphite was done by chemical oxidation with (NH4)(2)S2O8 and HNO3. Fourier-transform infrared spectra of graphite after chemical indicating surface oxidation of graphite surface. X-ray diffraction and scanning electron microscopic studies show the improvement of graphite structure without modification of crystalline structure. Electrochemical performance of lithium-ion cell assembled with developed anode material shows noticeable improvement of the reversible capacity and coulombic efficiency in the first cycle and cycling behavior after surface modification.
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| 3. |
- Amaraweera, T. H. N. G., et al.
(författare)
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Synthesis of Li(Ni1/3Mn1/3Co1/3-xBax)O-2 cathode materials for lithium-ion rechargeable battery by glycine-nitrate combustion process
- 2019
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Ingår i: Ionics. - : Springer Science and Business Media LLC. - 0947-7047 .- 1862-0760. ; 25:6, s. 2501-2507
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Tidskriftsartikel (refereegranskat)abstract
- This study was based on developing Li(Ni1/3Mn1/3Co1/3-xBax)O-2 (x=0.04, 0.08, 0.11, 0.22, and 0.33) materials by substituting expensive Co with Ba, for the use in the cathode of rechargeable lithium-ion batteries (LIBs). Glycine-nitrate combustion method, which is a low-cost combustion technique, was employed to synthesize spherical shaped micron size secondary particles formed by densely agglomerated primary particles. The phase analysis performed by the X-ray diffractometry revealed the formation of the required layered phase of R-3m structure with trace amounts of a secondary phase. Furthermore, these Ba-substituted novel materials showed considerably higher electrical conductivity than those of the Li(Ni1/3Co1/3Mn1/3)O-2 base material. In the cell performance studies, the Ba-substituted cathode materials synthesized in this study showed slightly lower initial discharge capacity of 162.4mAhg(-1) but with considerably improved cycle performance compared to those of the Li(Ni1/3Co1/3Mn1/3)O-2 base material (187.7mAhg(-1)). More importantly, the Li(Ni1/3Mn1/3Co1/3-xBax)O-2, x=0.04 material clearly showed its ability to eliminate and prevent structural transformation usually associated with excess Li extraction at potentials above 4.5V. Therefore, the Li(Ni1/3Mn1/3Co1/3-xBax)O-2, x=0.04 material can be proposed as a potential candidate for the high-voltage cathode application of LIB.
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| 4. |
- Bandara, T M W J, 1968, et al.
(författare)
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Electrical and complex dielectric behaviour of composite polymer electrolyte based on PEO, alumina and tetrapropylammonium iodide
- 2017
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Ingår i: Ionics. - : Springer Science and Business Media LLC. - 0947-7047 .- 1862-0760. ; 23:7, s. 1711-1719
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the electrical, dielectric and morphological analysis of composite solid polymer electrolytes containing polyethylene oxide, alumina nano-fillers and tetrapropylammonium iodide are conducted. The temperature dependence of conductivity shows activation energy of 0.23, 0.20 and 0.29 eV for electrolytes containing 0, 5 and 15 wt.% alumina, respectively, when data fitted to the Arrhenius equation. These activation energy values are in good agreement with those determined from dielectric measurements. The result confirms the fact that conductivity is activated by both the mobility and the charge carrier density. The conductivity isotherms demonstrated the existence of two peaks, at 5 and 15 wt.% Al2O3 composition. The highest conductivity values of 2.4 × 10−4, 3.3 × 10−4 and 4.2 × 10−4 S cm−1 are obtained for the sample with 5 wt.% Al2O3 at 0, 12 and 24 °C, respectively, suggesting an enhancement of conductivity compared with that of alumina free samples.
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| 5. |
- Bandara, T M W J, 1968, et al.
(författare)
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Transport parameters of charge carriers in PEO-LiTf-based, plasticized, composite, and plasticized-composite electrolytes intended for Li-ion batteries
- 2022
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Ingår i: Ionics. - : Springer Science and Business Media LLC. - 0947-7047 .- 1862-0760. ; 28:6, s. 2701-2714
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Tidskriftsartikel (refereegranskat)abstract
- Solid polymer electrolytes are a key component in many electrochemical devices such as dye-sensitized solar cells, batteries, and supercapacitors. In this study, three electrolytes based on polyethylene oxide (PEO) host polymer, ethylene carbonate (EC) plasticizer, and Al2O3 filler were investigated. The polymer electrolytes (PEO)9(EC)9(LiCF3SO3)2, (PEO)9(LiCF3SO3)2(Al2O3)0.75, and (PEO)9(EC)9(LiCF3SO3)2(Al2O3)0.75 were characterized by analyzing DC conductivity, the frequency dependence of AC conductivity, and complex dielectric function. The conductivities of the plasticized, composite, and plasticized-composite electrolytes at 26 °C increase from 6.25, 0.009, and 2.96 mS cm-1 to 21.5, 0.12, and 11.4 mS cm-1, respectively, when the temperature increased to 70 °C. For the in-depth analysis of electrolytes, dielectric analysis was used to determine the charge carrier density (n), mobility (μ), and diffusion coefficient (D) using a newly developed method. Further, the investigation extended to study the temperature dependence of n, D, and μ. The study reveals that EC can increase the ionic conductivity by increasing n, and conversely, filler contributes by increasing μ, respectively. At 26 °C, (PEO)9(EC)9(LiCF3SO3)2(Al2O3)0.75 shows D, μ, and n of 3.8×10-11 m2 s-1, 1.5×10-9 m2 V-1 s-1, and 1.3×1027 m-3, respectively. The values obtained for D, μ, and n parameters of the plasticized electrolytes agree with those available for similar electrolytes, while the composite electrolyte showed considerably lower values for n. The complex impedance analysis can be used to determine transport parameters of all the types (plasticized, composite, and plasticized composite) of polymer electrolytes.
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| 6. |
- Biradar, Bhimaraya R., et al.
(författare)
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Fabrication of supercapacitor electrode material using carbon derived from waste printer cartridge
- 2024
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Ingår i: Ionics (Kiel). - : SPRINGER HEIDELBERG. - 0947-7047 .- 1862-0760.
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Tidskriftsartikel (refereegranskat)abstract
- Transforming recyclable materials into a suitable product is an important area of research nowadays. This report demonstrates that carbon material derived from waste printer cartridges can be exploited to fabricate electrochemical cells-particularly supercapacitors (SCs). SCs are electrochemical energy storage devices currently attracting much attention in the research community due to their salient features, such as cost-effectiveness, extended cycle stability, and durability. Here, we report the results of thoroughly examining the effects of acidic, basic, and neutral aqueous electrolytes on printer waste carbon electrode material in SC efficiency. In our work, the waste carbon collected from used printer cartridges shows a specific capacitance of 178.4 F/g with energy and power density of 24.77 Wh/kg and 999.68 W/kg, respectively, at 0.5 A/g current density in acidic (1 M H2SO4) electrolyte medium. Moreover, it exhibited very promising capacitance of 135.04 F/g and 87.04 F/g in basic (1 M LiOH) and neutral (1 M NaCl) electrolyte medium, respectively, at 0.8 A/g current density with considerably better cycle stability. In an acidic medium, printer waste carbon drives a DC motor for 1 min with a three-cell series arrangement. The properties of that waste carbon (extracted from the cartridges) are similar to high-rate activated carbon available commercially.
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| 7. |
- Bokalawela, R., 0, et al.
(författare)
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H-2/Pt/Ce0.9Gd0.1O1.95/Pt/O-2 fuel cell operated in the intermediate temperature range 500-700 degrees C
- 2004
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Ingår i: IONICS. - 0947-7047 .- 1862-0760. ; 10:1-2, s. 84-87
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Konferensbidrag (refereegranskat)abstract
- Ce0.9Gd0.1O1.95 (GCO), is one of the potential candidate electrolytes for intermediate temperature Solid Oxide Fuel Cells (ITSOFC). GCO has high oxide ion conductivity in the intermediate temperature range (500 - 700 degrees C) compared to other C1-yGdyO2-2/y compositions and the Gd3+ ion is the most appropriate dopant material compared to other rare earth materials such as Sm3+, Y3+, Zr3+, etc. Our results show that the fuel cell H-2/Pt/Ce0.9Gd0.1O1.95/O-2 operated in the temperature range 500 - 700 degrees C gives the maximum power densities 0.0049 W/cm(2) at 500 degrees C and 0.0126 W/cm(2) at 650 degrees C for cell voltages 0.6275 V and 0.6278 V, respectively, where the electrolyte was kept in 5% H-2(+ Argon) for 12 hours before use in the fuel cell. Maximum power densities are 0.0038 W/cm(2) at 500 degrees C and 0.0270 W/cm(2) at 650 degrees C for cell voltages 0.5986 and 0.5913 V, respectively, where the electrolyte was kept in 2 % O-2(+ Argon) for 12 hours before use in the fuel cell.
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| 8. |
- Isidorsson, Jan, et al.
(författare)
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Physical and Electrochemical properties of Li-intercalated Sn oxide films made by sputtering
- 1995
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Ingår i: Ionics (Kiel). - 0947-7047 .- 1862-0760. ; 1:5-6, s. 400-405
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Tidskriftsartikel (refereegranskat)abstract
- Sn oxide films were made by reactive rf magnetron sputtering under conditions that led to both electronic and ionic conductivity. The film structure was studied by X-ray diffraction and Atomic Force Microscopy (AFM). Li+ intercalation produced electrochromism with coloration efficiency peaked in the infrared. Cyclic voltammograms taken at different sweep rates were interpreted in terms of a unique structural parameter related to the fractal dimension of a self-affine surface relief and in excellent agreement with the fractal dimension as obtained with AFM. Mössbauer spectroscopy was used to determine the valence state of the Sn-atoms; a change from Sn4+ to Sn2+ was detected after electrochemical intercalation of Li+.
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| 9. |
- Ragupathi, V., et al.
(författare)
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Enhanced electrochemical performance of LiMnBO3 with conductive glassy phase : a prospective cathode material for lithium-ion battery
- 2017
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Ingår i: Ionics (Kiel). - : Springer. - 0947-7047 .- 1862-0760. ; 23:7, s. 1645-1653
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Tidskriftsartikel (refereegranskat)abstract
- LiMnBO3 has been identified as a promising cathode material for next-generation lithium-ion batteries. In this study, LiMnBO3 along with glassy lithium borate material (LiMnBO3 (II)) is synthesized by sol-gel method. X-ray diffraction (XRD) analysis depicts the existence of LiBO2 glassy phase along with m-LiMnBO3 phase. Transmission electron microscopy (TEM) analysis confirms the presence of LiBO2 glassy phase. An enhanced electrical conductivity of 3.64 x 10(-7) S/cm is observed for LiMnBO3 (II). The LiBO2 glassy phase is found to promote the Li reaction kinetics in LiMnBO3 (II). The synthesized LiMnBO3 (II) delivers a first discharge capacity of 310 mAh g(-1) within a potential window of 1.5-4.5 V at C/10 rate. Further, a discharge capacity of 186 mAh g(-1) at the 27th cycle shows a better cycle performance. The enhanced capacity is due to the presence of LiBO2 glassy phase and more than one Li-ion transfer in the lithium-rich stoichiometry of LiMnBO3 (II). Density functional theory calculation reveals the exact electronic structure of m-LiMnBO3 with a band gap of 3.05 eV. A charge transfer mechanism is predicted for delithiation process of m-LiMnBO3.
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| 10. |
- Smulko, J., et al.
(författare)
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Quality Assessments of Electrochromic Devices : The possible use of 1/f current noise
- 2007
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Ingår i: Ionics (Kiel). - : Springer Science and Business Media LLC. - 0947-7047 .- 1862-0760. ; 13:3, s. 179-182
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Tidskriftsartikel (refereegranskat)abstract
- Electrochromic (EC) devices, capable of modulating their optical transmittance by charge insertion/extraction, were produced by laminating films comprised of nanoporous W oxide and Ni–V oxide by a polymer electrolyte and having this three-layer stack between transparent conducting In2O3:Sn films backed by polyester foils. 1/f noise in the current (I) was observed when the charged (colored) EC device was discharged via a resistor. The power spectral density S i at fixed frequency scaled as S i ∼ I 2. Extended color/bleach cycling degraded the optical quality and homogeneity of the device and concomitantly increased the 1/f noise intensity. These initial data indicate that 1/f noise has a potential to serve as a quality measure for EC devices.
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