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Investigation of electrode Investigation of electrode materials with 3DOM structuresmaterials with 3DOM structures
Antony HanAntony HanChem 750/7530Chem 750/7530
OutlineOutline
Introduction of Lithium-ion batteries and Introduction of Lithium-ion batteries and 3DOM materials3DOM materials
Objects of the projectObjects of the project
Synthetic techniqueSynthetic technique
Preliminary result on electrode materials Preliminary result on electrode materials with 3DOM structurewith 3DOM structure
ReferenceReference
Applications of Li-ion batteries Applications of Li-ion batteries
Lithium ions intercalation and Lithium ions intercalation and de-intercalation process de-intercalation process
Parameters to evaluate electrode materialsParameters to evaluate electrode materials
First charge/discharge capacitiesFirst charge/discharge capacities
Irreversible capacities between each Irreversible capacities between each charge/discharge cyclecharge/discharge cycle
Charge/discharge cycleabilitiesCharge/discharge cycleabilities
Charge/discharge rate capacityCharge/discharge rate capacity
Volumetric charge/discharge capacitiesVolumetric charge/discharge capacities
Electrical conductivitiesElectrical conductivities
What is 3DOM?What is 3DOM?
3DOM structure = 3 dimensional ordered 3DOM structure = 3 dimensional ordered macroporous structuremacroporous structure
Replicas of their colloidal-crystal templates Replicas of their colloidal-crystal templates
Nanometer-sized wallsNanometer-sized walls
Well-interconnected close-packed Well-interconnected close-packed spherical voids with sub-micron diameters spherical voids with sub-micron diameters
Both cathode and anode materials can be Both cathode and anode materials can be fabricated into 3DOM structurefabricated into 3DOM structure
ComparisonComparison
Conventional electrode materialsConventional electrode materials Volumetric capacitiesVolumetric capacities Stable cycleabilityStable cycleability
3DOM electrode materials3DOM electrode materials Solid-state diffusion distance Electrode–electrolyte interface and Li-ion
conduction through the electrolyte.
Objects of the projectObjects of the project
Preparation of the colloidal crystal templates Preparation of the colloidal crystal templates used for the generation of 3DOM materials; used for the generation of 3DOM materials; Methods of integration of the precursors of Methods of integration of the precursors of electrode materials into the colloidal crystal electrode materials into the colloidal crystal templates;templates;Methods of removal of the colloidal crystal Methods of removal of the colloidal crystal templates according to the different properties of templates according to the different properties of electrode materials;electrode materials;Electrochemistry performance of these as-Electrochemistry performance of these as-prepared 3DOM electrode materials. prepared 3DOM electrode materials.
Synthesis routeSynthesis route
Current Opinion in Solid State and Materials Science 5 (2001) 553–564
TemplateTemplateDesired propertiesDesired properties Easier template removalEasier template removal Possibility of providing additional functionalityPossibility of providing additional functionality Max the precursor loading (easy access of the voids)Max the precursor loading (easy access of the voids)
Preparation methodsPreparation methods Gravity sedimentationGravity sedimentation CentrifugationCentrifugation Vertical depositionVertical deposition Templated depositionTemplated deposition ElectrophoresisElectrophoresis PatterningPatterning Controlled dryingControlled drying
Loading techniqueLoading technique
Methods to load the fluid precursorsMethods to load the fluid precursors Sol-gel chemistrySol-gel chemistry PolymerizationPolymerization Salt-precipitation and chemical conversionSalt-precipitation and chemical conversion Chemical vapour deposition (CVD)Chemical vapour deposition (CVD) Spraying techniquesSpraying techniques Nanocrystal deposition and sinteringNanocrystal deposition and sintering Oxide and salt reductionOxide and salt reduction ElectrodepositionElectrodeposition Electroless deposition, Electroless deposition,
Template removal techniqueTemplate removal technique
Polymer templatesPolymer templates Calcination simultaneously with conversion of Calcination simultaneously with conversion of
the precursor to a solid in the desired phase.the precursor to a solid in the desired phase. If the solidification is feasible at low If the solidification is feasible at low
temperatures, spheres can also be extracted temperatures, spheres can also be extracted with appropriate solvents, such as toluene or with appropriate solvents, such as toluene or tetrahydrofuran (THF)/acetone mixtures.tetrahydrofuran (THF)/acetone mixtures.
Silica sphere templates are removed by Silica sphere templates are removed by dissolution in aqueous HF solutions. dissolution in aqueous HF solutions.
CharacterizationCharacterization
Powder X-ray diffractometer (PXRD)Powder X-ray diffractometer (PXRD)
Scanning electron microscope (SEM)Scanning electron microscope (SEM)
Brunauer-Emmett-Teller (BET)Brunauer-Emmett-Teller (BET)
Energy dispersive spectroscopy (EDS)Energy dispersive spectroscopy (EDS)
Electrochemical characterization (coin cell Electrochemical characterization (coin cell type batteries)type batteries)
Some of preliminary resultsSome of preliminary results
J. of Electro. Soc., 152 10 A1989 2005
LiCoOLiCoO22 with 3DOM structures with 3DOM structures
Co3O4 impurity exists-high surface area
Optimize synthesis conditionsOptimize synthesis conditions
1.3 Li composition • minimum impurity• maintain the structure
Size controlSize control
PEG doped• Grain size still grewPt doped• Much smaller size
ElectrochemistryElectrochemistry
• Bulk LiCoO2• Better charge/discharge cycleabilities• Poor rate capacity
• 3DOM LiCoO2
• Relatively poor cycleabilities• Capacity still remains at very high charge/discharge rate
ReferenceReference
Ergang, N. S.; Lytle, J. C.; Yan, H.; Stein, A.; “The Effect of a Ergang, N. S.; Lytle, J. C.; Yan, H.; Stein, A.; “The Effect of a Macropore Structure on Cycling Rates of LiCoOMacropore Structure on Cycling Rates of LiCoO22” ” J. Electrochem. J. Electrochem. Soc.Soc. 2005, 2005, 152152, A1989-A1995., A1989-A1995.Lee, K. T.; Lytle, J. C.; Ergang, N. S.; Oh, S. M.; Stein, A.; Lee, K. T.; Lytle, J. C.; Ergang, N. S.; Oh, S. M.; Stein, A.; “Synthesis and Rate Performance of Monolithic Macroporous “Synthesis and Rate Performance of Monolithic Macroporous Carbon Electrodes for Lithium Secondary Batteries”, Carbon Electrodes for Lithium Secondary Batteries”, Adv. Funct. Adv. Funct. Mater.Mater. 2005, 2005, 1515, 547-556., 547-556.Lytle, J. C.; Yan, H.; Ergang, N. S.; Smyrl, W. H.; Stein, A.; Lytle, J. C.; Yan, H.; Ergang, N. S.; Smyrl, W. H.; Stein, A.; “Structural and electrochemical properties of three-dimensionally “Structural and electrochemical properties of three-dimensionally ordered macroporous tin(IV) oxide films”, ordered macroporous tin(IV) oxide films”, J. Mater. Chem.J. Mater. Chem. 2004, 2004, 1414, , 1616-1622.1616-1622.Yan, H.; Sokolov, S.; Lytle, J. C.; Stein, A.; Zhang, F.; Smyrl, W. H.; Yan, H.; Sokolov, S.; Lytle, J. C.; Stein, A.; Zhang, F.; Smyrl, W. H.; "Colloidal-Crystal-Templated Synthesis of Ordered Macroporous "Colloidal-Crystal-Templated Synthesis of Ordered Macroporous Electrode Materials for Lithium Secondary Batteries", J. Electrode Materials for Lithium Secondary Batteries", J. Electrochem. Soc. 2003, 150, A1102-A1107.Electrochem. Soc. 2003, 150, A1102-A1107.