Brief history of the battery

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Brief history of the battery
Battery University online
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First battery
-0.76V vs SHE
0.34V vs SHE
Total voltage 1.1 V
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Energy Storage Lithium ion battery
e-
e-
Discharged state
Charged state
Discharging
Cathode
Anode
C (graphite anode) Co3O4 (cobalt oxide anode)
LiC6 (graphite anode) Li2O/Coo (cobalt oxide
anode)
FePO4 cathode CoO2 cathode
LiFePO4 cathode LiCoO2 cathode
Li
LiPF6
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Common to all Li ion batteries

• Conducting current collectors
• Anode
• Cathode
• Electrolyte
• Seperator

Tarascon, J.M. Armand, M., Nature, 414, (2001)
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Conducting current collectors

• Lightweight, typically metallic
• Chemically resistant
• Stable at cell voltages

Stainless steel anode current collector
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Seperators permeability and stability

• Must be an electronic insulator
• Must be ionic conductor
• Chemically resistant
• Stable in electrolyte

Read Arora, P., and Ahengming, Z., Chemical
Reviews, 2004, 4419-4462
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Electrolyte

• The electrolyte must be a good ionic conductor,
  and an electronic insulator
• Must be stable at necessary potentials and
  temperatures
• Performs minimal side reactions with electrodes
• Much of battery failure and degradation is caused
  by electrolyte side reactions

Xu, K., Chemical Reviews, 2004 4303-4417
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Safety concerns with current Li ion batteries
drive to higher potential anodes

• Safety improvements
• Electrolyte stabilization
• Li dendrite formation

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Lithium plating and dendrites
Xu, K., Chemical Reviews, 2004 4303-4417
Tarascon, J.M. Armand, M., Nature, 414, (2001)
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Cathode SEI and internal resistance

• Cathodes can be fouled by degradation of
  electrolyte on the surface of the material
• For instance Ethyl carbonate can form polymeric
  olefins on the surface of the electrode
• Typically the SEI is a poor ion conductor and
  will increase the internal resistance of the
  battery

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Internal resistance

• The internal resistance increases in the battery
  over time
• The actual voltage output is never exactly the
  same when current is being drawn from the battery
  as when there is no current being drawn
• The higher the internal resistance is, the lower
  the observed voltage will be when

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Internal resistance measurement

• Measured by intentionally shorting the battery
  using a defined resistor
• Once the internal resistance is known, the
  maximum cell output can be calculated
• Internal resistance is a function of SEI,
  electrode conductivity, and surface area

DV1.22 V
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Chemical energy storage

• Cell potential is determined by the difference in
  Gibbs free energy of the Lithium in the anode and
  cathode
• The electrodes must allow ions to flow through
  them
• This is helped by using layered structures
• Making nanoscale materials
• Coating or percolating the system with conducting
  material
• How do we measure battery materials?
• Specific Capacity
• Energy
• Power
• Ragone plot
• Galvanostatic measurement

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Chemistries of electrodes

• Most common electrode system is that of LiCoO2
  and graphite

0.1 V vs. Li
3.8-3.9 V vs. Li
3.7 V total
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Characterization

• The cell voltage is the average voltage of the
  discharge cycle
• LiCoO2 has an average discharge voltage of 3.7 V

From Nokia
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Other Cathode Materials
LiFePO4
Li2MnSiO4
1. Ohzuku, T. Brodd, R. J., J.Power Sources
2007, 174, (2), 449-456 2. Amatucci, G. G.
Pereira, N., J. Fluorine Chemistry 2007, 128,
(4), 243-262 3. Howard, W. F. Spotnitz, R. M.,
J. Power Sources 2007, 165, (2), 887-891.
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Capacity calculation on a typical anode
Capacity calculated for cobalt oxide to be 881
mAh/g
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Volume changes in battery electrodes

• Metallic anodes behave entirely different from
  typical oxide anodes
• Typically a metal will form an alloy with lithium
  by formally reducing the lithium
• Failures in metallic anodes are usually due to
  volume changes
• Volume changes literally cause for the electrode
  to be destroyed
• Most alloying electrodes are not stable for more
  than a couple charge/discharge cycles

Tirado, J.L., Materials Science and Engineering R
40, 2003, 103-136
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Gold or metallic anodes

• Au anode can alloy with lithium (this is not the
  same as graphite being plated with lithium
• Phases of gold/lithium alloys
• Ag and Au can have several alloy phases (AgLi9 or
  Au4Li15)
• There are many systems that can form alloys with
  lithium (tin or silicon) but the volumetric
  expansion is so great that the electrode is
  unstable
• These electrodes are special in that they
  actually catalyze the reduction of Li to Lio
• This catalysis has various potentials vs. Li
  metal, typically around 0.7 V

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Alloy forming anodes for Lithium ion batteries

• Au or Ag capable of alloying with Li up to
  AgLi9 and Au4Li15 at very negative potential
• Advantages in minimizing cell voltage reduction
• High theoretical capacity

Taillades, 2002, Sold State Ionics
http//www.asminternational.org/
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Pure Au viral nanowires

• Plateaus
• 0.2 and 0.1 V/discharge
• 0.2 and 0.45V/charge
• Capacity from 2nd cycle
• 501 mAh/g AuLi3.69

Diameter 40 nm, free surface
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Discharge/charge curves from the first two cycles
Au0.9Ag0.1
Au0.5Ag0.5 Au0.67Ag0.33 Gradual
changes in potential during discharge Capacity
at 2nd cycle 499 for Au0.5Ag0.5 459 for
Au0.67Ag0.33
Au0.9Ag0.1 Curve shape similar with Au Capacity
at 2nd cycle 439
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Calculating capacity for Gold Anode
Capacity is measured in mAh/g and is a measure of
the amount of current you can get out of your
electrode with respect to mass
This will yield an overall capacity of 445.9
mAh/g
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Calculating capacity for Gold Anode
Use the theoretical capacity to determine the
charge rate First find the active mass, not
everything in the electrode is active
Example a 2 mg electrode with 20 inactive
material (super P and PTFE binder)
In order to discharge this electrode over one
hour, apply a -0.499 mA current
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Coin cell assembly

• Used Mortar and Pestle to prepare electrodes
• Added binder to roll out electrode
• Assemble into coin cell

Stainless steel anode current collector
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Testing battery on Solartron
16 channels for testing batteries
8 coin cell testers
Celltest program for measurement and analysis
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Preparing test schedule
Battery measurements are done on the Solartron
using the program Celltest In order to test the
battery, place in coin cell holder Celltest
works in a simple order, first make a test
schedule, then an experiment, then run.
Each test schedule will consist of Initial rest
that lasts one minute (this is just to make sure
that the coin cell is being tested correctly) A
discharge step A charge step
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Preparing test schedule
Do a 1C charge and discharge
Change to current control
Constant for 60 hours
Type in calculated charge/discharge current
(negative for discharge)
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Preparing test schedule
Measure on change
On termination tab jump to next step based on
voltage 0.1V for discharge, 2.5V for charge
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Preparing a Celltest experiment
Save data file as your group name
Select your test schedule to run on the correct
channel
You must set safety limits of 5 V and 4 A, in
case something got connected incorrectly
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Calculating actual capacity for Gold Anode
After running the electrode the data that will be
available will be the negative applied current,
the time of the measurement and the mass of
active material Use the current (in milliAmps),
time (in hours) and the mass (in grams) to
determine the actual capacity for your anode
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The Ragone chart
Necessary for comparing different energy
types For comparison Gasoline has an energy
density of 12 kWh/kg and nuclear fission can
yield 25 billion Wh/kg The chart plots the total
amount of energy stored vs how quickly the energy
if made available
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Rate Capability of a-FePO4 nanowire/SWCNTs
conjugate templated on different phages.
Ragone plot showing improvement in high power
performance with higher binding affinity
towards SWCNTs
Well-dispersed SWCNTs even with smaller amount
alone make better electric wiring to active
materials due to better percolation networks than
super p carbon powders.
Tested 2 V and 4.3 V
Y. J. Lee et al., Science 324, 1051 (May, 2009).
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Amount of material to provide electricity for one
hour, one day, one week and one month with no
external energy production

• Daily short term
• For short term daily energy storage, 50 kg of
  Li-ion batteries, will provide all electrical
  needs of the average household
• Long term
• Insolation never drops below 50 of the average
  throughout the year (even on the cloudiest day!),
  so with gt50 energy production by solar, two 2000
  gallon tanks will provide all electricity
  required for the three months of winter if they
  can be adequately charged during the summer months

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Helpful websites

• http//www.sandia.gov/ess/About/projects.html
• http//www.eia.doe.gov/fuelelectric.html (Nearly
  all information on energy production and
  consumption in the US)
• http//rredc.nrel.gov/solar/old_data/nsrdb/redbook
  /atlas/ (information on solar energy)
• http//www.electricitystorage.org