Overview
Batteries, fuel cells,
and supercapacitors are the technologies that meet society’s growing need for energy
storage and conversion. Inkjet and aerosol jet printing of these devices provides
the opportunity to improve their performance by optimizing their structures at
the micro and meso scales. Printing also permits integration of energy storage
devices directly into the systems they power. Our research focuses on the four areas
necessary to transform the idea of printed energy storage into a manufacturing
reality: 1) printable electroactive materials; 2) functional
inks containing electroactive materials; 3) inkjet and aerosol jet printing methods
for layer by layer construction of electrochemical devices; 4) post-printing
processing protocols to optimize device performance.
Printable Electroactive Materials
Active and selective electrocatalysts
and conductive support materials are the functioning components of
electrochemical devices for energy conversion and storage. Our recent
work in this area focuses on synthesis and mechanistic studies of a printable Ni(OH)2/graphene oxide catalyst for the oxygen reduction reaction, and on
mechanochemical synthesis of printable high surface area, high porosity graphite-based
support material.
Ink Formulation
The high conductivity
and surface area of graphene make it a potentially useful support material and
conductive additive in electrodes. To enable environmentally friendly printing
of graphene, we are working on formulating a high concentration aqueous graphene
ink. Our approach is to synthesize a graphene material with a low density of
edge functionalities. These edge functionalities allow the graphene material to
attain a zeta potential such that it is self-dispersible in pH-tuned aqueous
solution.
Digital Fabrication of Electrocatalytic Devices
Lithium ion batteries
are the dominant energy storage technology for mature applications like
portable electronics, and emerging applications like electric vehicles. Our
research in this area focuses on aerosol jet printing of high capacity, rate
capable Li-ion battery cathodes. Our research also focuses on aerosol jet
printing solid electrolyte materials for the next generation of all solid
Li-ion batteries.
Post-Printing Processing
A crucial step in fabricating electrochemical devices is consolidation of material from the form of an ink dispersion in which it is deposited to the solid form of a functioning device.
Consolidation always includes evaporation of solvent, and can also include higher
temperature sintering steps. Our research in this area focuses on understanding
the interfaces formed when Li-ion battery cathode materials are co-sintered
with solid electrolyte materials like ceramics and glasses.