The students developed a processing method to produce a high energy density micro-lithium ion battery for powering microelectronic devices. They fabricated a battery with a volume of 37mm3, smaller than any commercial lithium ion battery, that was able to charge and discharge with the desired voltage and capacity. The battery demonstrated stable charging over 40 cycles at 80-90% of theoretical maximum capacity. It also maintained hermetic sealing when submerged in water for a month with no leakage, showing promise for powering sealed microelectronic systems. Future work will focus on improving energy density, processing consistency, and cycle life.

1. Development of a High Energy Density Micro-Lithium Ion Battery
Omri Flaisher (ME), Chad Hucey (ME), Nathan Martel (ChE)
Advisor: Professor Yan Wang
Rationale
Testing
Processing Method
Achievements Future Work
Micro-fabrication techniques have
enabled production of increasingly
compact electrical microsystems.
Micro-lithium ion battery technology
currently lacks the characteristics
required to power microelectronics
that require energy sources.
Hermeticity Test
• Seal lithium metal in cell
• Put cell under water and in
atmospheric environment
• Aluminum rod
precision machined
and grinded to
interference fit
• Metal-to-glass
junction sealed with
epoxy
• Optimize packaging with new designs
and/or materials
• Improve electrode structure to
achieve 3D architecture
• Improve cell’s ability to maintain
potential once charged
• Improve processing consistency
• Improve energy density and cycle life
Objectives
• Develop a processing method to produce an
operational micro-lithium ion battery
• Develop a packaging technique that can
effectively seal the battery
• Develop a separator capable of being injected
• Test battery performance in terms of charge
capacity, energy density, and cycle life
Acknowledgements
Polymer Gel Electrolyte
• Stable charging over 40 cycles
• Charge capacity at 80% - 90%
theoretical maximum
• Performance comparable to
commercial separators
• Professor Yan Wang
• Qina Sa – Graduate Student
• Zhangfeng Zheng – Graduate Student
• Kevin Arruda – WPI Machine Shop
• Roger Steele – Physics Department
Polymer Gel Electrolyte Test
• Synthesize PGE separator
• Test performance using
Swagelok Cell
Micro-Battery Test
• Perform single cycle charge and
discharge tests at various C
rates
• Cycle battery until failure
Micro-Battery
• Produced operational micro-lithium
ion battery of 37 mm3
• Smaller than any commercial
LiCoO2/Graphite Li-ion battery
• Produced desired voltage and a
charge/discharge capacity
Hermeticity
• No water leakage for 1 month
• LiCoO2 solution injected
into half sealed cell
• Heated in oven to:
evaporate solvent, create
porosity, form conductive
adhesion
• PGE separator
solution injected
on electrode
• Heated in oven to
create gel
separator
• Graphite anode
solution injected
onto copper current
collector
• Heated in oven to
form desired
properties • Final processing occurred in
argon glove box environment
• Electrolyte inserted followed by
anode coated current collector
• Epoxy applied to metal-to-glass
junction
Note: Battery above to left made with
gap separator
• No air leakage during test duration
5mm
4 mm
3mm
4 mmBattery
MEMS Sensor