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.