Author: Kinson Chihang Kam
Publisher:
ISBN:
Category : Cathodes
Languages : en
Pages : 108

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Author: Dong Zhang
Publisher:
ISBN:
Category :
Languages : en
Pages : 282

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Author: Pierre Lucas
Publisher:
ISBN:
Category : Lithium cells
Languages : en
Pages : 290

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Author: Sengupta, Surajit
Publisher: Library and Archives Canada = Bibliothèque et Archives Canada
ISBN: 9780494028490
Category :
Languages : en
Pages : 338

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To observe the effect of physical properties on battery performance cyclic chronopotentiometric evaluation was conducted. It has been found with these synthesized materials that there is an increase in the 1st discharge capacity with an increase in the annealing time and the temperature at both 1C and C/5 rates. This increase is more significant when the annealing temperature is 600°C as compared to that at 250°C. This implies that an increase in particle size may improve the initial discharge capacity. It was observed that at the discharge rate of 1C, the material annealed at 600°C for 8 hours showed the best performance with respect to an average initial discharge capacity, energy density and capacity retention. However, it was found that the initial discharge capacity, the energy density and the capacity retention are poor for highly crystalline, micron sized lithium manganese oxide cathode material. (Abstract shortened by UMI.)Lithium-based batteries are potential candidates to provide maximum volumetric and gravimetric energy density. One of the most attractive candidates as a cathode material for secondary lithium ion battery systems is the spinel LiMn 2O4 because it is environmentally friendly, less expensive and is capable of providing high energy density as compared to other cathode materials that are currently available. One problem associated with the spinel structure is capacity fading during multiple cycles of charge and discharge operations. This behaviour is due in part to the structural distortion during deep charge and discharge where nearly 100% of the lithium is extracted and inserted inside the spinel structure. Capacity fading can also be caused by dissolution of manganese ions in the electrolyte phase. A solution based method has been adapted for the synthesis of lithium manganese oxide, and chromium and cobalt doped mixed oxide materials using polyvinyl alcohol (PVA) as a chelating agent. It has been found from TGA/DSC analysis that at around 220°C the synthesis reaction is completed. The precursor powders obtained were annealed at different temperatures and times in the range of 250°C to 600°C and from 2 to 8 hours respectively to obtain pure spinel oxides. From X-ray analysis it has been observed that the crystallite size can be controlled in the range of approximately 6 nm to 32 nm depending on the annealing time and the temperature. The morphology of the synthesized materials consisted of submicron sized particles agglomerated with micropores inside the network structure.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: 陳文勤
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Hanaa Abuzeid
Publisher: LAP Lambert Academic Publishing
ISBN: 9783659301704
Category :
Languages : en
Pages : 192

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Using cheap and environment benign alternative oxides as cathodes in batteries is the current trend to give cheap, environmently benign and high energeytic cathode material instead of the commerecial one of high excepensive, toxic and unstable LiCoO2 used in lithium ion batteries. Using alpha-manganese dioxides of the tunnel structure with their modifications by using Sn and Co as dopants as cathodes in alkaline batteries.

Author: Brandon Joseph Kelly
Publisher:
ISBN:
Category : Cathodes
Languages : en
Pages : 236

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Author: Evelyn Kai-Hua Ng
Publisher:
ISBN: 9780494213032
Category :
Languages : en
Pages : 110

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Lithium ion batteries deliver the highest specific energy and energy density of commercially available secondary batteries. The objective of this study was to evaluate lithium-manganese phosphate (LiMnPO4) for potential application as a cathode material in lithium ion batteries due to its high theoretical capacity and stable phospho-olivine structure. LiMnPO 4 was successfully synthesized via a novel aqueous sol-gel process under an inert nitrogen and air atmosphere. Microstructural design strategies including annealing treatment and the addition of 1 wt% copper dopant were evaluated in order to improve the electrochemical performance of the LiMnPO4 cathode. The cathode particle microstructure and morphology were characterized using X-ray diffraction and scanning electron microscopy. Open circuit voltage was 4.1 V for all samples. The electrochemical performance of LiMnPO 4 is significantly improved by the addition of a dopant in an inert nitrogen atmosphere with a specific capacity of 28 mAh/g achieved during the first discharge cycle.

Author: Subbarao Surampudi
Publisher: The Electrochemical Society
ISBN: 9781566772105
Category : Technology & Engineering
Languages : en
Pages : 594

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