Crystallite Size Control and Resulting Electrochemistry of Magnetite, Fe[sub 3]O[sub 4]

Zhu, Shali; Marschilok, Amy C.; Takeuchi, Esther S.; Takeuchi, Kenneth J.

doi:10.1149/1.3078076

Cited by 57 publications

(86 citation statements)

References 35 publications

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“…11,12 Larger sized nanocrystalline magnetite, ∼32 nm, was purchased from Alfa Aesar. X-ray diffraction data was collected using a Rigaku Smart Lab diffractometer with Cu Kα radiation.…”

Section: Methods Of Approachmentioning

confidence: 99%

Modeling the Mesoscale Transport of Lithium-Magnetite Electrodes Using Insight from Discharge and Voltage Recovery Experiments

Knehr

Brady

Cama

et al. 2015

J. Electrochem. Soc.

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100

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A multi-scale mathematical model, which accounts for mass transport on the crystal and agglomerate length-scales, is used to investigate the electrochemical performance of lithium-magnetite electrochemical cells. Experimental discharge and voltage recovery data are compared to three sets of simulations, which incorporate crystal-only, agglomerate-only, or multi-scale transport effects. Mass transport diffusion coefficients are determined by fitting the simulated voltage recovery times to experimental data. In addition, a further extension of the multi-scale model is proposed which accounts for the impact of agglomerate size distributions on electrochemical performance. The results of the study indicate that, depending on the crystal size, the low utilization of the active material is caused by transport limitations on the agglomerate and/or crystal length-scales. For electrodes composed of small crystals (6 and 8 nm diameters), it is concluded that the transport limitations in the agglomerate are primarily responsible for the long voltage recovery times and low utilization of the active mass. In the electrodes composed of large crystals (32 nm diameter), the slow voltage recovery is attributed to transport limitations on both the agglomerate and crystal length-scales. Large increases in the use of distributed and intermittent energy sources (i.e., wind and solar) have increased the need for cost effective, reliable, and efficient energy storage technologies.1 To address these needs, significant research efforts have focused on the development of next generation materials for secondary batteries, which can provide inexpensive and long lasting energy storage solutions.2-4 In particular, considerable work has focused on the advancement of magnetite (Fe 3 O 4 ) as an electrode in lithium-ion batteries due to its high theoretical capacity (926 mAh g −1 ), low cost and safety (non-toxic). 5-14Despite these advantages, one of the major challenges limiting the advancement of magnetite electrodes is a considerable difference between the maximum, theoretical capacity and the observed, experimental capacity of the active material. This difference increases the anticipated cost of magnetite batteries because it requires the electrodes to be overdesigned with excess amounts of active material. The difference between the theoretical and experimental capacity is related to the close-packed inverse spinel structure of Fe 3 O 4 , which restricts the transport of lithium in the material. To address this issue, several authors have synthesized Fe 3 O 4 nano-crystallites in attempts to minimize the path length for ion transport.9-14 The smaller path length increases the utilization of the active material by making it possible for ions to penetrate to the center of the crystals, especially at high rates of discharge. Electrodes fabricated with nano-crystalline magnetite have shown significant improvement in capacity; however, the theoretical capacity has still proven difficult to obtain.11 Further improvements in capacity may requir...

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“…11,12 Larger sized nanocrystalline magnetite, ∼32 nm, was purchased from Alfa Aesar. X-ray diffraction data was collected using a Rigaku Smart Lab diffractometer with Cu Kα radiation.…”

Section: Methods Of Approachmentioning

confidence: 99%

Modeling the Mesoscale Transport of Lithium-Magnetite Electrodes Using Insight from Discharge and Voltage Recovery Experiments

Knehr

Brady

Cama

et al. 2015

J. Electrochem. Soc.

Self Cite

100

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“…Thus, especially for applications demanding high power output, control of material properties including crystallite size can be especially useful. 8,9 To rationalize our observed bifunctional correlation of Fe 2+ concentration and crystallite size ( Fig. 1), we hypothesize that heterogeneous nucleation was dominant at low concentration, and homogeneous nucleation was dominant at high concentration.…”

Section: Control Of Physical Propertiesmentioning

confidence: 72%

Secondary Battery Science: At the Confluence of Electrochemistry and Materials Engineering

2012

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Considerations of energy density, power, and calendar life are critical to effectively develop advanced secondary systems. For next generation battery applications requiring multiple features including long life, large cycle count, high energy density and high power, new strategies are needed for the rational design of electroactive materials and electrodes. This article discusses several conceptual approaches under exploration with examples from our research group. The first approach is the systematic synthesis of materials with structures facilitating ion insertion and deinsertion at high voltage and energy density, where we control materials properties such as surface area, particle size and in particular crystallite size. A second approach is the investigation of novel electrode structures and substrates to increase energy density and capacity retention under cycling, where we have developed strategies for minimizing passive components. A third approach is investigation of catalysts for metal air batteries where the cathode active material is drawn from the air rather than carried in the battery.

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“…14 Crystallite size and sample purity were determined using X-ray powder diffraction (XRD) on a Rigaku Ultima-IV diffractometer with Cu Kα measured in a 2θ range from 5-90…”

Section: Methodsmentioning

confidence: 99%

The Electrochemistry of Fe₃O₄/Polypyrrole Composite Electrodes in Lithium-Ion Cells: The Role of Polypyrrole in Capacity Retention

Bruck

Gannett

Bock

et al. 2016

J. Electrochem. Soc.

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Two series of magnetite (Fe 3 O 4 ) composite electrodes, one group with and one group without added carbon, containing varying quantities of polypyrrole (PPy), and a non-conductive polyvinylidene difluoride (PVDF) binder were constructed and then analyzed using electrochemical and spectroscopic techniques. Galvanostatic cycling and alternating current (AC) impedance measurements were used in tandem to measure delivered capacity, capacity retention, and the related impedance at various stages of discharge and charge. Further, the reversibility of Fe 3 O 4 to iron metal (Fe 0 ) conversion observed during discharge was quantitatively assessed exsitu using X-ray Absorption Spectroscopy (XAS). The Fe 3 O 4 composite containing the largest weight fraction of PPy (20 wt%) with added carbon demonstrated reduced irreversible capacity on initial cycles and improved cycling stability over 50 cycles, attributed to decreased reaction with the electrolyte in the presence of PPy. This study illustrated the beneficial role of PPy addition to Fe 3 O 4 based electrodes was not strongly related to improved electrical conductivity, but rather to improved ion transport related to the formation of a more favorable surface electrolyte interphase (SEI). Li-ion battery (LIB) technology has played a critical role in the widespread adoption of a variety of portable electronic devices. However, due to the applications-driven nature of batteries, especially ambitious capacity and power requirements by potentially new devices, there is an increasing need for the basic understanding of the complicated Li-ion related electrochemistries associated with new electroactive materials. For example, one strategy to increase the capacity of electroactive materials is to use materials capable of multi-electron transfer (such as conversion reactions) resulting in high energy density materials.1 Towards this end, magnetite, Fe 3 O 4 , is a promising nanoscale electroactive material with a high theoretical capacity (926 mAh/g) upon full conversion to Fe metal.2 Thus, over the past several years, the number of published studies of Fe 3 O 4 has been increasing due in part to its high energy density, as well as environmental friendliness and low cost.

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Crystallite Size Control and Resulting Electrochemistry of Magnetite, Fe[sub 3]O[sub 4]

Cited by 57 publications

References 35 publications

Modeling the Mesoscale Transport of Lithium-Magnetite Electrodes Using Insight from Discharge and Voltage Recovery Experiments

Modeling the Mesoscale Transport of Lithium-Magnetite Electrodes Using Insight from Discharge and Voltage Recovery Experiments

Secondary Battery Science: At the Confluence of Electrochemistry and Materials Engineering

The Electrochemistry of Fe₃O₄/Polypyrrole Composite Electrodes in Lithium-Ion Cells: The Role of Polypyrrole in Capacity Retention

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Crystallite Size Control and Resulting Electrochemistry of Magnetite, Fe[sub 3]O[sub 4]

Cited by 57 publications

References 35 publications

Modeling the Mesoscale Transport of Lithium-Magnetite Electrodes Using Insight from Discharge and Voltage Recovery Experiments

Modeling the Mesoscale Transport of Lithium-Magnetite Electrodes Using Insight from Discharge and Voltage Recovery Experiments

Secondary Battery Science: At the Confluence of Electrochemistry and Materials Engineering

The Electrochemistry of Fe3O4/Polypyrrole Composite Electrodes in Lithium-Ion Cells: The Role of Polypyrrole in Capacity Retention

Contact Info

Product

Resources

About

The Electrochemistry of Fe₃O₄/Polypyrrole Composite Electrodes in Lithium-Ion Cells: The Role of Polypyrrole in Capacity Retention