Structure studies on LiMn0.25Fe0.75PO4 by in-situ synchrotron X-ray diffraction analysis

Chen, Yi‐Chun; Chen, Jin‐Ming; Hsu, Chia-Haw; Shih, Han C.; Chang, Young-Il; Sheu, Hwo‐Shuenn

doi:10.1016/j.jpowsour.2008.07.088

Cited by 31 publications

(17 citation statements)

References 16 publications

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“…Therefore, it is necessary to remove the electrolyte and other possible deposits from the surface of active materials to achieve strong Raman signals. Besides, serious delay in structure evolution always appears in the in situ pattern during in situ observation because the structure transformation cannot follow the charge/discharge process step by step [32][33][34].…”

Section: Resultsmentioning

confidence: 99%

Design and comparison of ex situ and in situ devices for Raman characterization of lithium titanate anode material

Shu

Shui

et al. 2011

Ionics

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In this paper, ex situ and in situ devices for Raman observations are designed and compared with each other by using lithium titanate as working electrode. In situ cell is made for Raman spectroscopy based on a confocal microscope Raman spectrometer. The instant evolutions of lithium titanate anode material during cycle can be recorded by in situ Raman in detail. Although the in situ technique is an important method to monitor the structure evolution of lithium titanate, it is difficult to conduct an in situ experiment in most laboratories. Moreover, the existence of electrolyte and surface deposits weakens the Raman signals of sample. Therefore, the structure evolution of Li 4 Ti 5 O 12 cannot be described accurately. For comparison, air-free ex situ device is a simple and cheap tool to achieve the information from lithiated and delithiated samples. By removing the electrolyte and deposits on the sample with dimethyl carbonate, the ex situ Raman pattern shows higher signal to noise ratio than that of in situ Raman result. As a result, the shift and recovery of ex situ Raman bands confirms that the electrochemical reaction of Li 4 Ti 5 O 12 with Li in 0.0-2.0 V is not a fully reversible process but a partially reversible process.

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Section: Resultsmentioning

confidence: 99%

Design and comparison of ex situ and in situ devices for Raman characterization of lithium titanate anode material

Shu

Shui

et al. 2011

Ionics

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“…The partial substitution of Fe for Mn in LiFe 1-x Mn x PO 4 was considered to improve the cathode electrochemical performance [27][28][29] . It was shown that the cation-doping of LiMnPO 4 by electrochemically nonactive metals seems to be more attractive than the mixed Mn-Fe compounds, because along with its electrochemical performance improvement this provides a constant voltage operation of the material based on a single redox reaction Mn 3+ /Mn 2+ [30].…”

Section: Studies On High-performance Limnpo 4 Olivine Cathodementioning

confidence: 99%

LiMnPO4 Olivine as a Cathode for Lithium Batteries

Bakenov¹,

Taniguchi

2011

TOMSJ

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The olivine structured mixed lithium-transition metal phosphates LiMPO 4 (M = Fe, Mn, Co) have attracted tremendous attention of many research teams worldwide as a promising cathode materials for lithium batteries. Among them, lithium manganese phosphate LiMnPO 4 is the most promising considering its high theoretical capacity and operating voltage, low cost and environmental safety. Various techniques were applied to prepare this perspective cathode for lithium batteries. The solution based synthetic routes such as spray pyrolysis, precipitation, sol-gel, hydrothermal and polyol synthesis allow preparing nanostructured powders of LiMnPO 4 with enhanced electrochemical properties, which is mostly attributed to the higher chemical homogeneity and narrow particle size distribution of the material. Up-to-date, the LiMnPO 4 /C composites prepared by the spray pyrolysis route have the best electrochemical performance among the reported in the literature.

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“…The electrochemical performance can be improved by coating the samples' surface with carbon, or by doping with Fe atoms or nano-sized cathode materials. Olive phosphate materials combined with mixed transition-metal ions, such as LiFe 1´x Mn x PO 4 /C, have recently attracted considerable attention [3][4][5][6][7][8][9][10][11][12][13][14]. Zou et al [15] prepared LiFe 0.2 Mn 0.8 PO 4 /C cathode materials by a solid-state method and sucrose used as the carbon source.…”

Section: Introductionmentioning

confidence: 99%

The Carbon Additive Effect on Electrochemical Performance of LiFe0.5Mn0.5PO4/C Composites by a Simple Solid-State Method for Lithium Ion Batteries

2016

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This work reported a solid-state method to prepare LiFe 0.5 Mn 0.5 PO 4 /C (LFMP/C) composite cathode materials by using LiH 2 PO 4 , MnO 2 , Fe 2 O 3 , citric acid (C 6 H 8 O 7 ), and sucrose (C 12 H 22 O 11 ). The citric acid was used as a complex agent and C 12 H 22 O 11 was used as a carbon source. Two novel hollow carbon sphere (HCS) and nanoporous graphene (NP-GNS) additives were added into the LFMP/C composite to enhance electrochemical performance. The HCS and NP-GNS were prepared via a simple hydrothermal process. The characteristic properties of the composite cathode materials were examined by micro-Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), elemental analysis (EA), and alternating current (AC) impedance methods. The coin cell was used to investigate the electrochemical performance at various rates. It was found that the specific discharge capacities of LFMP/C + 2% NP-GNS + 2% HCS composite cathode materials were 161.18, 154.71. 148.82, and 120.00 mAh¨g´1 at 0.1C, 0.2C, 1C, and 10C rates, respectively. Moreover, they all showed the coulombic efficiency ca. 97%-98%. The advantage of the one-pot solid-state method can be easily scaled up for mass-production, as compared with the sol-gel method or hydrothermal method. Apparently, the LFMP/C composite with HCS and NP-GNS conductors can be a good candidate for high-power Li-ion battery applications.

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Structure studies on LiMn0.25Fe0.75PO4 by in-situ synchrotron X-ray diffraction analysis

Cited by 31 publications

References 16 publications

Design and comparison of ex situ and in situ devices for Raman characterization of lithium titanate anode material

Design and comparison of ex situ and in situ devices for Raman characterization of lithium titanate anode material

LiMnPO4 Olivine as a Cathode for Lithium Batteries

The Carbon Additive Effect on Electrochemical Performance of LiFe0.5Mn0.5PO4/C Composites by a Simple Solid-State Method for Lithium Ion Batteries

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