Automotive Engineering - December 2023 - BET-24

brittle materials. They often break in response
to strain and pressure. Making these
materials more ductile would allow them
to withstand stress by flowing instead of
cracking. This behavior can be achieved
with some techniques that introduce small
crystal defects into ceramic electrolytes.
Electrons leave a system through anodes.
In SSBs, this component can be
made from pure lithium, which is the
most energy dense metal. Although this
material offers advantages for a battery's
power, it also creates pressure that can
damage electrolytes.
" During charging, nonuniform plating
and an absence of stress-relief mechanisms
can create stress concentrations.
These can support large amounts of pressure,
enabling the flow of lithium metal, "
said Erik Herbert, the leader of ORNL's
Mechanical Properties and Mechanics
group. " In order to optimize the performance
and longevity of SSBs, we need to
engineer the next generation of anodes
and solid electrolytes that can maintain
mechanically stable interfaces without
fracturing the solid electrolyte separator. "
The team's work is part of ORNL's long
history of researching materials for SSBs.
In the early 1990s, a glassy electrolyte
known as lithium phosphorous oxynitride,
or LiPON, was developed at the lab. LiPON
has become widely used as an electrolyte
in thin-film batteries that have a metallic
lithium anode. This component can
withstand many charge-discharge cycles
without failure, largely due to the ductility
of LiPON. When met with mechanical
stressors, it flows instead of cracking.
" In recent years we have learned that
The image conceptualizes the processing, structure, and mechanical behavior of glassy ion
conductors for solid state lithium batteries. (Image: Adam Malin/ORNL, U.S. Dept. of Energy)
LiPON has robust mechanical properties
to complement its chemical and electrochemical
durability, " said Nancy Dudney,
an ORNL Scientist who led the team that
developed the material.
The team's effort highlights an under-studied
aspect of SSBs - understanding
the factors that shape their lifespan
and efficacy. " The research community
needed a road map, " said Kalnaus. " In
our paper, we outlined the mechanics
of materials for solid-state electrolytes,
encouraging scientists to consider these
when designing new batteries. "
For more information, contact Scott
Jones at onesg@ornl.gov; 865-241-6491.
New Gel Polymer Electrolyte to Revolutionize the Safety
of Li-Ion Batteries
The non-flammable polymer semi-solid electrolyte offers a promising solution to mitigate battery fires.
Ulsan National Institute of Science and Technology, Korea
A
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collaborative research team, led by
Professor Hyun-Kon Song in the
School of Energy and Chemical
Engineering at UNIST, Dr. Seo-Hyun Jung
from Research Center for Advanced Specialty
Chemicals at Korea Research Institute of
Chemical Technology (KRICT), and Dr. TaeHee
Kim from the Ulsan Advanced Energy
Technology R&D Center at Korea Institute
of Energy Research (KIER), has achieved a
groundbreaking milestone in battery technology.
Their remarkable achievement in
developing a non-flammable gel polymer
electrolyte (GPE) is set to revolutionize the
safety of lithium-ion (Li-ion) batteries by
mitigating the risks of thermal runaway and
fire incidents.
In the past, the potential flammability of
Li-ion batteries has raised significant concerns,
especially in electric vehicles, where
fire hazards pose a serious threat to underground
parking lots. Addressing this critical
issue, the research team has successfully developed
a groundbreaking non-flammable
polymer semi-solid electrolyte, offering a
promising solution to mitigate battery fires.
Conventionally, non-flammable electrolytes
have heavily relied on the incorporation
of flame-retardant additives or
solvents with exceptionally high boiling
points. However, these methods often resulted
in a considerable decrease in ion
conductivity, compromising the overall performance
of the electrolyte.
In their breakthrough research, the research
team introduced a trace amount
of polymer into the electrolyte, creating a
semi-solid electrolyte. This novel approach
dramatically increased the Li-ion conductivity
by 33 percent compared to existing
liquid electrolytes. Moreover, the pouchtype
batteries incorporating this non-flammable
semi-solid electrolyte exhibited a
remarkable 110 percent improvement in
life characteristics, effectively preventing
Battery & Electrification Technology, December 2023

Automotive Engineering - December 2023

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