1. General introduction on Lithium Ion Batteries

2. History of battery….
Pioneering work for the lithium battery began in 1912 by G. N. Lewis but it was not until the early 1970’s when the first non-rechargeable lithium batteries became commercially available. Attempts to develop rechargeable lithium batteries followed in the eighties, but failed due to safety problems.
the first commercial lithium-ion battery was released by Sony in The cells utilised layered oxide chemistry, specifically lithium cobalt oxide. These batteries revolutionised consumer electronics.

3. Michael Faraday
Charles-Augustin de Coulomb
demonstrated the relation between electricity and chemical bonding,
capacity (mAh/g) = [F × nLi) / ( M×3600)] × 1000
Where, F = Faraday’s constant( 96,500 coulombs per gm equivalent)
n Li = Number of Li per formula unit of the electrode material
M = Molecular mass of the electrode material.

4. Cell – Energy storage device that converts chemical energy present in to electrical energy.
Battery: Combination of one or more cell;
The cell components: Cathode, Anode and Electrolyte, seperator and current collector.
Primary Battery Secondary Battery
Zinc- MnO2: Inexpensive, small in size, voltage ~ 1.5V, use in watches, calculators etc, use and dispose,
Rechargeable cell , Ni- Cd, Li -Ion battery
Energy storage of the battery is means that How much charge a battery can deliver to the external circuit.
coulomb is defined as the quantity of electricity transported in one second by a current of one ampere. Named for the 18th–19th-century French physicist Charles-Augustin de Coulomb

5. Why Li-based power sources?
Li is the lightest metal (specific gravity ρ=0.53 g/cm3) high energy density
Theoretical capacity of Li : 3860 Ah/kg (Li Li+ + e-)
Extremely high compared to Zn (820 Ah/kg) and Pb (200 Ah/kg).

6. Salient Features of LIB
High Energy density, Light weight, design flexibility
Preferred choice for portable appliances
present world production per year is
~ 300 million cells.
Market value ~ US $ 200 Billion
expected growth up to ~ 40%
Courtesy of Panacenia.com.

7. Specification for the Commercial Battery fabricated by Panasonic.
Size (DWH)
3.83562 mm
Weight
15g
Nominal capacity
760 mAh
Nominal voltage
3.7 V
Charge voltage
4.2 V
Charge time
150 min.
Energy density (Volumetric)
375 Wh/dm3
Energy density(Gravimetric)
190 Wh/kg
Cycle performance
85% at 1000th cycle
Temperature range
-20C to + 60C
Cathode
LiCoO2
Anode
Graphite
Courtesy of Panasonic website

8. Principle of Operation
Discharging
Co Co3+
Charging
Co Co4+
Cathode: LiCoO Li1-xCoO2 + xLi+ + xe- (Oxidation: E° = 0.6V)
Anode: C + xLi+ + xe LixC (Reduction: E°=-3.0V)
Overall rxn: C + LiCoO LixC + Li1-xCoO2; x= (Ecell=3.6V)
(during charging)

9. LIB Technology
Different configurations : a) cylindrical b) coin c) prismatic d) thin and flat (pLiON) [ref. Nature 2001, Tarascon et al .]

10. Material Considerations
Anodes
Carbon anodes
Capacity~372 mAh/g
Graphite – layered, low capacity, high reversibility
Hard Carbon- Non-layered, high capacity. Irreversible capacity loss
Metal coating (Ag,Zn or Sn) of anodes tried

11. Amorphous Tin Composite Oxides (ATCO)
SnMxOy (x≥1), M = glass-forming elements (e.g. a mixture of B and P)
Gravimetric capacity- high (>600 mAh/g)
Sn2+,Sn4+/Sn redox couple
SnO + 2 (Li+ + e-) → Sn + Li2O
SnO2 + 4 (Li+ + e-) → Sn + 2Li2O
Sn (Li+ + e-) ↔ Li4.4Sn
Capacity-fading need to be solved before these materials can be used commercially
Irreversible loss of Li in Sn formation
Reversible capacity

12. Other options Lithium metal nitrides Inter-metallics Oxides
Pros: High capacity(~900 mAh/g), low average voltage
Cons: High moisture sensitivity, lack of economic manufacturing processes
Inter-metallics
Cu6Sn5 – Capacity fading
InSb – In (high cost), Sb (toxic)
Oxides
Spinel-type oxides- Li4Ti5O12, Li4Mn5O12 and Li2Mn4O12
Low voltage spinels + high-voltage cathodes= intermediate voltage Li-ion cells.
Do not produce metallic Li which is a safety concern in LiC6 or metallic lithium anodes.

13. Electrolytes Li salt dissolved in a solvent.
LIB Operation range : V, Decomposition potential of H2O = 1.23 V Aqueous electrolyte not used
4 types of non-aqueous electrolytes in use: liquid, gel, polymer and ceramic-solid electrolytes.

14. Liquid electrolytes
Highly ionizable Li-salts - LiPF6, LiAsF6 etc dissolved in organic carbonates - ethylene carbonate (EC), dimethyl carbonate (DMC) etc
Organic carbonates - aprotic, polar, high K, solvate Li salts at high concentration (>1M), good ionic conduction.
Problems : leakage, sealing, non-flexibility of the cells, side reactions with charged electrodes

15. Solid electrolytes
Crystalline or glassy matrix - Li ions move through vacant/interstitial sites - high σionic (~ S/cm at 25°C)
Crystalline : Nasicon framework phosphates – LiM2(PO4)3 and perovskite-based oxides, (Li,La)MO3 (M = Ge, Zr, Hf)
Glasses : oxides or sulfides
Advantages : (i) No leakage, (ii) Wide operating temperature range (iii) Better charge-discharge cycling profile (iv) Long life – little self discharge.

16. Polymer electrolyte
A salt dissolved in a high-molecular-weight polar polymer matrix
E.g. PEO (Poly-ethylene oxide)
Chemically stable – contains only C-O, C-C and C-H bonds.
Cation mobility - cation-ether-oxygen co-ordination bonds, regulation - local relaxation and segmental motion of the PEO polymer chains -> high σionic of the electrolyte.
Pros : ease of fabrication, flexibility, lightweight, leak proof
Cons: low conductivities at or below room temperature
Addressed by plasticized or gel electrolytes - polymer electrolytes with a component (solid or liquid): to enhance the ionic conductivity.

17. Layered Cathodes Layered materials
Facile Intercalation / deintercalation – high reversibility
α-NaFeO2 structure( sp grp R3m)
LiNiO2, LixCoO2 (widely in use, 140 mAh/g) – thermally stable : High cost, toxicity
LiMnO2 – cheap, substitution needed to stabilize the structure (Li1+x Mn0.5Cr0.5O2, 190 mAh/g )

18. NaSICON materials
Oxyanion scaffolded structures built from corner-sharing MO6 octahedra (where M is Fe, Ti, V or Nb) and XO4n tetrahedral anions (where X is S, P, As, Mo or W)
Polyoxyanionic structures possess M-O-X bonds
Altering the nature of X -> change (through an inductive effect) the iono-covalent character of the M-O bonding
Possible to tune M redox potentials.
Promising candidate - LiFePO4

19. Spinels LiMn2O4 - cubic spinel structure with sp grp Fd3m
Spinels - 3D hosts with Li ions occupying 8a tetrahedral sites.
Capacity fading and poor recyclability
Cost, non-toxicity and availability

20. Advanced Applications
Mars Exploration rover” spirit”
Koizumi taking a 10 minute spin
Eliica, Japan Speed – 90km/hr

21. Mechanical grinder
Tubular Furnace
Hydraulic press

22. Preparation of Composite Electrodes ( Cathode or Anode).
Fine powders of the active materials (LiCoO2, CaSnO3, etc) mixed with conducting carbon (Super PMMM) and PVDF in N-methyl pyrolidinone (NMP) solvent.
PVDF acts as binder that helps the thick film coating to adhere well to the metal foil.
This mixture of active material : conducting carbon :PVDF in fixed proportion ( in my case 70:15:15) was stirred to get the homogenous paste like slurry.
The Slurry was coated on to a clean Al or Cu foil. Thick film was dried at 100oC in an air.
Thick film coater
Furnace

23. 5. Electrode was then pressed between spherical twin roller at about
5. Electrode was then pressed between spherical twin roller at about KPa pressure. This ensures that the film of the composite electrode adheres to the Al/Cu foil.
6. Electrode was cut into circular discs (16mm). Thickness ~ 0.05 – 0.12mm
7. Electrode- discs were dried in vacuum oven at 800C for ~ 12 hrs.

24. 8. Electrode disc then transferred to the Glove Box.
O2 and H2O content
< 1ppm
Glove Box

25. Fabrication of Lithium - Ion Cell
Diameter of coin cell ( 2016) ~ 16mm and height 2.0mm
Parts of Coin cell –
Cup > 16mm diameter and plastic ring, separators ( polypropylene separators; Electronically nonconducting but solution/ion permeable) Steel spring for close packing. Finally cell was sealed using a press and transferred out the glove box
Punching Machine
Li ion - coin Cell
Micropipette

26. Electrochemical Characterization :
Galvanostatic Cycling and Potentiostatic Cycling:
Galvanostatic Mode: The output voltage of the cell is monitored at constant current.
Potentiostatic Mode: The current is monitored at a particular voltage
Multi cell analyzer BITRODE

27. Specific Capacity of the cell :
The capacity of the electrode material in the battery depends on the amount of Li that can be intercalated / deintercalated into the host structure.
Capacity: Number of Coulombs (Charge) in (amperes-hours) delivered by a battery.
Specific capacity: Amount of charge delivered per unit weight of electrode active material (Ah/g or mAh/g ).
Theoretical specific capacity of a Li – containing oxide is calculated by assuming that all the Li per formula unit of the oxide participate in the electrochemical reaction and is given by
Specific Theoretical capacity (mAh/g) = [F × nLi) / ( M×3600)] × 1000
Where, F = Faraday’s constant( 96,500 coulombs per gm equivalent)
nLi = Number of Li per formula unit of the electrode material
M = Molecular mass of the electrode material.

28. Theoretical Capacity of the Electrode Material:
Weight of the active electrode material × its theoretical specific capacity
Experimental Capacity: Our experimental value observed by BITRODE (mAh)
Specific Capacity: Experimental capacity / weight of Electrode Material.
Number of Lithium Ions de – intercalated from the cathode active material during charging process,
Charging Capacity of Electrode / Theoretical Capacity
Where charging capacity = Charging current × Charging time
In Coin – type cell the weights of electrodes ~ 8-15mg hence the current will be small.