Development and Application of Air-battery
Department of Materials Engineering
Speaker : Prof. Chao-Ming Huang (K. S. U.)
2013 Global energy consumption
Statistic of World Energy
From:http:/ BP Statistical Review of World Energy /
What is a hydrogen fuel cell ?
•Hydrogen fuel cells (HFCs) are a type of
•HFCs generate electricity by reduction and
oxidation reactions within the cell.
•They use three main components, a fuel, an
oxidant and an electrolyte.
•HFCs operate like batteries, although they
require external fuel.
•HFCs are a thermodynamically open system.
•HFCs use hydrogen as a fuel, oxygen as an oxidant,
a proton exchange membrane as an electrolyte, and
emit only water as waste.
Different type of fuel cell comparsion
How do they work?
Fuel (H2) is first transported to the
anode of the cell
Fuel undergoes the anode reaction
Anode reaction splits the fuel into
H+ (a proton) and e-
Protons pass through the
electrolyte to the cathode
Electrons can not pass through the
electrolyte, and must travel
through an external circuit which
creates a usable electric current
Protons and electrons reach the
cathode, and undergo the cathode
• Schematic representation of Zn-air cell
Commercial, primary Zn-air batteries have been used for many years:
– Initially used as large batteries for applications such as railroad signaling,
remote communications, and ocean navigational units requiring long term, low
– With the development of thin electrodes, used in small, high capacity primary
cells, such as for hearing aids, small electronics, and medical devices.
Refuelable Zn-Air Cells
• Santa Barbara Municipal Transit District “Downtown
Waterfront Electric Shuttle”
• Powered by refuelable Zn-air cells.
• Road test underscored potential of such vehicles.
– 250 mile range between refueling
– Rapid refueling (10 minutes)
– Highway safe acceleration
Refuelable Zn-Air cells
• Primary Zn-air batteries have been very successful commercially.
• To take the technology to the next level, i.e, developing secondary,
electrically rechargeable batteries, or using Zn-air technologies for vehicle
propulsion, significant challenges must still be overcome:
– Understand the chemistry of the zincate anion in an alkaline solution.
– Develop stable bifunctional catalysts for both the oxygen reduction
reaction and oxygen evolution reaction.
– The air electrode should be optimized to reduce internal resistance.
Current Battery Outlook
• Metal-air batteries have attracted much attention
recently as a possible alternative, due to their
extremely high energy density compared to that of
other rechargeable batteries:
Why Li-air ?
• Extremely high specific capacity of Li anode material (3842 mAh g-1 for lithium,
vs. 815 mAh g-1 for Zinc)
• The couple voltage of Li-O2 in alkaline electrolytes is 2.91 V (compared to 1.65
• The Li-air battery, when fully developed, could have practical specific energies of
300 Wh kg-1
• Li-air cell electrically rechargeable
Different type of battery comparsion
Secondary Li-Air Cells
• How are Li-air cells rechargeable?
Li(s) → Li+ + e(anode reaction)
Li+ + ½O2 + e- → ½Li2O2
Li+ + e- + ¼O2 → ½Li2O
• In 2006, Bruce et al. demonstrated that Li2O2 is formed on charging and
decomposes according to the reaction below:
Li2O2 → O2 + 2Li+ + 2e-
Li - air Architectures
Configuration of Li - air
The critical differences between Li-ion and Li-Air are:
Li-Air battery is an open system, because of oxygen is obtained from air
MnOx based catalysts
•Catalysts will not only affect ORR & OER potential, but they also influence the specific
MnO2 is the most common ORR catalyst for metal-air battery, because it is cheap & stable;
Besides, their ORR-catalytic activity (ORR poential ~ 2.6 V) can compare with most efficient
catalyst—Pt( 2.6 V)
The Bruce group had investigated various MnOx catalysts(α,β,γ, -MnO2& Mn2O3, Mn3O4)
higher capacity, duo
to high surface area
Capacity can achieve ~3000 mAh/g
Discharge @ a rate of 70 mA/cm2 & 1 atm O2
The structure of αMnO2 possesses 2x2
Air Electrode Requirements
• Cathode must be able to sustain an oxygen reduction reaction
(and oxidation if battery is rechargeable).
• Cathode must be highly porous.
• Catalysts are typically incorporated into the carbon layer.
Factors that affect performance
• Most metals are unstable in water and react with the electrolyte to corrode the
metal, resulting in self-discharge.
• Electrode carbonation: Absorption of CO2 (since the cell is an open system),
results in crystallization of carbonate in the air electrode, clogging pores and
• Water transpiration: Movement of water vapor either into or out of the cell.
– Excessive water loss can lead to drying of the cell and premature failure.
– Excessive gain of water can dilute the electrolyte.
LaMnO3 Perovskite system
oxygen reduction reaction (ORR)
good redox properties,
tunable catalytic performance.
P123 (Triblock Copolymer)
Journal of the Taiwan Institute of Chemical Engineers
45 (2014) 2334–2339 (SCI, IF = 2.637)
very fine particles
specific surface area. ↑
pore volume. ↑
Discharge voltages ↑
↑ cycling stability
↑ discharge voltage 1.090 V→1.158 V
pure phase. LaMnO3
large surface area. 2.8X
high pore volume. 4X
Energy density = 885 W h/kg(Zn consumption)
current density =25 mA/cm2
discharge voltage = 1.18 V
• Zinc Air Battery
• Cathode : Catalysts
• Anode : Zinc
• Electrolyte : NaOH, KOH
(Oxygen Reduction Reaction, ORR)
(Oxygen Evolution Reaction, OER)
PS: potentiostatic, 定電壓
GS: galvanostatic, 定電流
CV: cyclic voltammogram, 循環伏安
1000 2000 3000 4000
Time: 5 min
Global air battery prediction
New Tesla Patent: 400-Mile Battery
Pack Using Metal-Air & Lithium-Ion
Air Battery System
New Tesla Patent: Electric Vehicle Extended Range
Hybrid Battery Pack System
▪ Patent : US 20130181511
▪ A power source comprised of a first battery pack (e.g., a
non-metal-air battery pack) and a second battery pack (e.g.,
a metal-air battery pack) is provided, wherein the second
battery pack is used when the user selects an extended range
mode of operation. Minimizing use of the second battery
pack prevents it from undergoing unnecessary, and
potentially lifetime limiting, charge cycles.
• Metal-air batteries offer great benefits if they can be
harnessed to their fullest potential.
• Recap of Zn-air vs. Li-air: