Characterisation of olivine-type LiMnxFe1−xPO4 cathode materials

Yao, Jane; Bewlay, S.; Konstantionv, K.; Drozd, Vadym; Liu, R.S.; Wang, X.L.; Liu, H.K.; Wang, G.X.

doi:10.1016/j.jallcom.2006.01.038

Cited by 48 publications

(45 citation statements)

References 19 publications

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Specifically, the prospect of improved energy density over LiFePO 4 due to the higher redox potential of Mn 3+ / Mn 2+ compared to Fe 3+ / Fe 2+ ͓ϳ4.1 V compared to ϳ3.4 V vs Li/ Li + ͑Ref. 16͔͒ has fuelled research into Li͑Fe 1−y Mn y ͒PO 4 .…”

Section: Introductionmentioning

confidence: 99%

“…16͔͒ has fuelled research into Li͑Fe 1−y Mn y ͒PO 4 . 1,3,[5][6][7]11 Several questions in particular arise for mixed cation systems: LiFePO 4 is delithiated in a two-phase reaction forming FePO 4 , and both phases tolerate only a small amount of off-stoichiometry. 17 Zhou et al showed that this two-phase reaction is unusual and driven by the strong electron-Li + interaction.…”

Section: Introductionmentioning

confidence: 99%

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Phase diagram and electrochemical properties of mixed olivines from first-principles calculations

2009

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Using first-principles calculations, we study the effect of cation substitution on the transition-metal sublattice in phospho-olivines, with special attention given to the Li x ͑Fe 1−y Mn y ͒PO 4 system. We use a cluster expansion model derived from first-principles with Monte Carlo simulations to calculate finite-T phase diagrams, voltage curves, and solubility limits of the system. The phase diagram of Li x ͑Fe 1−y Mn y ͒PO 4 shows two lowtemperature miscibility gaps separated by a solid solution phase centered at Li composition x Ϸ y, which corresponds to a state where most Fe ions are oxidized and most Mn are not. This intermediate low-T solid solution is stabilized by the dilution of phase-separating interactions caused by the disorder of redox potentials on the transition-metal sites. The calculated voltage curves show two plateaus at ϳ4 -4.2 V and ϳ3.5-3.7 V, corresponding to the Mn 3+ / Mn 2+ and Fe 3+ / Fe 2+ redox couples, respectively, with an extended sloping region in between corresponding to the low-T solid solution phase. In agreement with experiment, we find that the Mn 3+ / Mn 2+ ͑Fe 3+ / Fe 2+ ͒ voltage is decreased ͑increased͒ by Fe ͑Mn͒ substitution. We explain this by considering the energy of the solid solution which is the discharged ͑charged͒ state for these redox couples and argue that such changes are generic to all mixed olivine systems. We also find reduced phase transformation polarization on both plateaus which we attribute to the decreased composition difference between the oxidized and reduced state for each redox couple

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Phase diagram and electrochemical properties of mixed olivines from first-principles calculations

2009

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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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“…Similar mixing techniques have been used in previous attempts to improve the performance of α-LiMnPO 4 . [7][8][9] In this paper we focus specifically on Li 3 Fe 0.2 Mn 0.8 CO 3 PO 4 . Since complete Li-Na exchange is much easier to perform in Li 3 FeCO 3 PO 4 than in Li 3 MnCO 3 PO 4 , we expect this compound to ion-exchange more completely from its sodium-containing parent compound than Li 3 MnCO 3 PO 4 .…”

mentioning

confidence: 99%

“…Similar mixing techniques have been used in previous attempts to improve the performance of α-LiMnPO 4 . [7][8][9] In this paper we focus specifically on Li 3 • C and magnetically stirred for 44 hours, all in an Ar-flushed glove box. Next, the reaction products were separated from the ion-exchange solution and washed by centrifuging in the native solution, followed by centrifuging in methanol, distilled water, and methanol again.…”

mentioning

confidence: 99%

Electrochemical Properties of Li3Fe0.2Mn0.8CO3PO4 as a Li-Ion Battery Cathode

Matts

Chen

Ceder

2013

ECS Electrochemistry Letters

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Previously conducted high-throughput ab initio calculations have identified carbonophosphates as a new class of polyanion cathode materials. Li 3 MnCO 3 PO 4 is the most promising candidate due to its high theoretical capacity and ideal voltage range. However, a major limitation of this material is its poor cyclability and experimentally observed capacity. In this work we synthesize Li 3 The need for lithium-ion batteries with higher energy density than existing materials has led to significant efforts to discover new cathode materials.1-3 High-throughput ab initio computation is an effective approach employed to accelerate the process of materials discovery. 4 This has led to the identification of several novel lithium intercalation materials. 3,5,6 One class of novel materials that has been predicted to function as intercalation cathodes for Li-ion batteries is the lithium transition metal carbonophosphates. 5 The Li 3 FeCO 3 PO 4 and Li 3 MnCO 3 PO 4 compounds are of particular interest, as shown in Table I, which shows data first reported by Chen et al. 3 Both are predicted to have accessible 2 + to 3 + redox couples, but the 3 + to 4 + couple in the manganese-containing compound is also expected to be active at a voltage compatible with existing electrolytes. As a result, Li 3 MnCO 3 PO 4 is of the greatest interest because it has a high theoretical capacity of 231 mAh/g and average voltage of 3.7 V. As polyanionic cathodes, lithium metal carbonophosphates could also be preferred over oxide cathode materials since they are generally less likely to release oxygen at high voltages. 4 The synthesis and characterization of both Li 3 FeCO 3 PO 4 and Li 3 MnCO 3 PO 4 have been previously reported.3 The lithiumcontaining carbonophosphates are not thermodynamic ground states, so the compounds are synthesized using ion-exchange techniques from the thermodynamically stable sodium carbonophosphates. As reported previously by Chen et al., Li 3 FeCO 3 PO 4 has a theoretical capacity of 115 mAh/g and can be easily synthesized using ion exchange methods. This compound cycles reversibly, close to its theoretical limit at a rate of C/5. In contrast, Li 3 MnCO 3 PO 4 shows a discharge capacity of 135 mAh/g on its first discharge at a rate of C/100, which is only ∼58% of its theoretical capacity. In addition, the capacity of Li 3 MnCO 3 PO 4 degrades in subsequent cycles. The poor performance in Li 3 MnCO 3 PO 4 could be due to many factors. However, we believe one major cause is the residual sodium (∼17%) ions sitting on Li sites as a result of an incomplete ion exchange during synthesis. The better-performing Li 3 FeCO 3 PO 4 shows no residual sodium after synthesis. 3Our approach is to substitute manganese in the Li 3 MnCO 3 PO 4 with iron to improve its performance by imparting the ion-exchangeability and cycling performance of the Li 3 FeCO 3 PO 4 on to Li 3 MnCO 3 PO 4 . Similar mixing techniques have been used in previous attempts to improve the performance of α-LiMnPO 4 . [7][8][9] In this paper we focus specifically...

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Characterisation of olivine-type LiMnxFe1−xPO4 cathode materials

Cited by 48 publications

References 19 publications

Phase diagram and electrochemical properties of mixed olivines from first-principles calculations

Phase diagram and electrochemical properties of mixed olivines from first-principles calculations

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

Electrochemical Properties of Li3Fe0.2Mn0.8CO3PO4 as a Li-Ion Battery Cathode

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