Material and electrolyte for pseudocapacitor

Faridah Hanum Bt Hj Anuar SA10069

Rabiatul Adawiyah Bt Muslim SA10079

Nurul Ain Bt Ahmad Zamri SA10097Izzati Bt Ahmad Fuad SA10045Nurul Najwa Bt Mustafa

SA10100

SILVER-DOPED MANGANESE OXIDE PSEUDOCAPACITOR

ELECTRODES

SPECIALITY OF MnO2

More practical

Inexpensive Pseudocapacitive

Material

Exhibits theoretical specific

capacitance of approximately

1,100 Fg through stochiometric

reduction of MnO2 to MnOOH in a

potential window of 1V

BUT!!

The capacitance for thick MnO2

film is ultimately limited by the

poor electrical conductivity of

MnO2

The stability of EC in the thin

MnO2 film configuration is

restricted because of low mass

loading

How To Overcome The Problems?

To overcome the electrical resistance of

MnO2, Silver (Ag) was incorparate into

MnO2 thin films.

Why?

Ag mass loading was accomplished

using cathodic eletrodeposition which

lead to higher specific capacitance

compare to pure MnO2 films

EXPERIMENTAL

1. CHEMICALS AND MATERIALS

2. ELECTRODEPOSITION

3. STRUCTURAL AND MORPHOLOGICAL CHARACTERIZATION

4. ELECTROCHEMICAL EVALUATION

CHEMICAL STRUCTURE OF Ag-Doped MnO2

1. CYCLIC VOLTAMETRY

ELECTROCHEMICAL EVALUATION

2.ELECTROCHEMICAL IMPENDANCE SPECTROSCOPY

MATERIAL 2Ruthenium

Oxides Materials

Ruthenium Oxides Materials

About :

High theoretical specific capacitance : 1358 F g-1

High electrical conductivity : 3Å~102 Ω-1 cm‑1

Ruthenium Oxides Materials Amorphous hydrous RuO2 prepared

by sol-gel methods with Specific capacitance of 720 F g-1 High capacitance is attributed to

hydrous surface layers that enable facile transport of electrons and protons

The capacitance decreased rapidly at higher rates due to proton depletion and over-saturation in the electrolyte during charge-discharge cycling

A two-dimensionally controlled RuO2 nano-sheet was invented for better electronproton transport

How to improve the rate performance?

Small particles of hydrous RuO2 can combine with carbon materials, such as with activated carbons,12-15 carbon black (CB),16 and CNTs.

Improve the rate capability of hydrous RuO2.

Ruthenium Oxides Materials

Ruthenium Oxides Materials

Figure 1 : Proposed pseudocapacitor materials in the literature.

Ruthenium Oxides MaterialsConclusion

ECs based on RuO2 and other oxides including MnO2 and NiO are better configured in aqueous media and some of them are being investigated for miniaturized devices because of their cost effectiveness.

SOLID ELECTROLYTE Composed of RbAg4I5

increase energy storage without causing dendrite growth

serves as an ionic conductor for the ionic part of the current

within

solid - state cell

Conductivity Range = 10-3 S/cm <σ< 10 S/cm

Ions carry the current

Conductivity decreases exponentially as temperature

decreases

GENERAL CHARACTERISTICS : SOLID ELECTROLYTES1. A large number of the ions of one species should be mobile. This

requires a large number of empty sites, either vacancies or accessible interstitial sites. Empty sites are needed for ions to move through the lattice.

2. The empty and occupied sites should have similar potential energies with a low activation energy barrier for jumping between neighboring sites. High activation energy decreases carrier mobility, very stable sites (deep potential energy wells) lead to carrier localization.

3. The structure should have solid framework, preferable 3D, permeated by open channels. The migrating ion lattice should be “molten”, so that a solid framework of the other ions is needed in order to prevent the entire material from melting.

4. The framework ions (usually anions) should be highly polarizable. Such ions can deform to stabilize transition state geometries of the migrating ion through covalent interactions.

OTHER SOLID ELECTROLYTE MATERIALSNAFION ®

Tetra methylammonium penta hydrate (also known

as hydrated TMAH5 )Li+ Ion Conductors

LiCoO2, LiNiO2

LiMnO2

Lithium aluminium oxide (Li5AlO4) F- Ion Conductors

PbF2 & AF2 (A = Ba, Sr, Ca)

SOLID ELECTROLYTE ADVANTAGES

- Freedom from fluid leakage

- Low ionic conductivities- Feasibility of small layer

thickness- Can be deeply discharged

many times- Long lifetime : high or low

temperature

LIQUID ELECTROLYTE BATTERY

INTRODUCTION

A battery containing a liquid solution of acid and water.

Other names are flooded cell and wet cell battery

2 different types:i.primary battery-non

rechargeableii.secondary battery-

rechargeable

Example: Lead acid battery

An electrical storage device that uses a reversible chemical reaction to store energy.

It uses a combination of lead plates or grids and an electrolyte consisting of a diluted sulphuric acid to convert electrical energy into potential chemical energy and back again.

The electrolyte of lead-acid batteries is hazardous to our health and may produce burns and other permanent damage if we come into contact with it.

DISCHARGEThe discharge process is driven by the

conduction of electrons from the negative plate back into the cell at the positive plate in the external circuit.

Negative plate reaction: Pb(s) + HSO−4(aq) → PbSO4(s) + H+

(aq) + 2-e Positive plate reaction:

PbO2(s) + HSO−4(aq) + 3H+(aq) + 2-e → PbSO4(s) + 2H2O(l) The total reaction can be written:

Pb(s) + PbO2(s) + 2H2SO4(aq) → 2PbSO4(s) + 2H2O(l)

Charging

The charging process is driven by the forcible removal of electrons from the positive plate and the forcible introduction of them to the negative plate by the charging source.

Negative plate reaction: PbSO4(s) + H+(aq) + 2-e → Pb(s) + HSO−4(aq)

Positive plate reaction: PbSO4(s) + 2H2O(l) → PbO2(s) + HSO−4(aq) + 3H+(aq) + 2-e

ADVANTAGE

Low cost. Reliable. Over 140 years of

development.Robust. Tolerant to abuse.Tolerant to overcharging. Low internal impedance.Can deliver very high currents. Indefinite shelf life if stored without

electrolyte. Can be left on trickle or float charge for

prolonged periods. Wide range of sizes and capacities

available.Mature secondary batteriesGlobally manufactured

DISADVANTAGES

Very heavy and bulky.

Danger of overheating during

charging

Not suitable for fast charging

low energy density

Cause environmental damage,

which is environmentally

unfriendly.

Ionic Liquid

ELECTROLYTE

Ionic liquidDefined as salts consisting entirely of ions

i) melting points lower than 100 °C - ionic conductivity is very high.

ii) very low vapor pressures- are not flammable, even if they consist of organic compounds.

Two class of ionic liquid :i) aprotic or conventionalii) protic ionic liquids (PILs).

- generally prepared by a neutralization reaction of an organic base like amine and an acid.

- If both are strong enough, proton transfer from the acid to the base occurs.

- Depending on the strength of the acid and base the degree of proton transfer changes.

Ionic liquid ElectrolyteMost common cation classes of ionic

liquids are i. Quaternary ammoniumii. Imidazolium, iii. Pyridiniumiv. Phosphonium

Physico-chemical propertiesi. Viscosityii. solubility propertiesiii. densityiv. acidity/basicityv. coordination propertiesvi. stereochemistry

Importance of ionic liquid

Melt at ambient temperature

Because ionic liquids are composed of only

ions, they show very high ionic conductivity,

non-volatility, and non-flammability.

The non-flammability and non-volatility

inherent in ion conductive liquids open new

possibilities in other fields as well.

multi-purpose materials, so there should be

considerable

(and unexpected) applications.

Viscosity physico – chemical propertiesViscosity of Imidazolium-Based Ionic Liquids

at Elevated Pressures : Cation and Anion

Effects by Azita Ahosseini and Aaron M.

Scurto

Ionic liquid used : Imidazolium – based

Common cation classes and anions used with ionic liquids.

Schematic diagram to test the viscosity using viscometer

(c) Modified TiO2 nanoparticles. (d) Diffusion of I3-through a matrix of (A) modified

and (B) unmodified TiO2 nanoparticles.

Proposed process for the extraction of cesium from aqueous tank waste using n-Bu3MeNNTf2

- + BOBCalixC6.

Advantages of ionic liquid It is possible to “engineer” the

physicochemical properties of RTILs by the

choice of the ionic constituents.

use of these liquids as electrolytes for Li

batteries and low-temperature fuel cells.

The non-volatile electrolyte solution will

change the performance of electronic and

ionic devices.

will be composed of organic ions, and these

organic compounds will have unlimited

structural variations because of the easy

preparation of many components.

Disadvantage of ionic liquidThe benefits of replacing the volatile

organic solvent component far

outweigh this disadvantage.

Low electrolytic conductivity

Need of tight closure to isolate from

atmospheric moisture

High environmental impact

High cost