Page 11 - ME News 2021 from the Penn State Department of Mechanical Engineering

Research Highlights
In pursuit of of commercially-adoptable electric vehicle batteries with
twice the energy density and cycle life
of current technology Penn State researchers have been awarded $2 9 million from the U S Department of Energy Donghai Wang professor of of mechanical engineering engineering and and chemical engineering engineering and and and affiliate of the Penn State Battery and and and Energy Energy Storage Technology Center Institutes of Energy Energy and and and the the Environment and and the the Materials Research Institute Institute has received funding for two projects to to tackle challenges related to to lithium- sulfur batteries This new class of batteries which use sulfur in in addition to to to lithium within their cores have the the the potential to to to store double the the the energy of lithium-ion batteries at at the the same weight and are significantly
less expensive to produce However the the presence of sulfur and lithium also causes the battery cycling to become unstable “It’s a a a a a promising technology ” Wang said “We want to to to push this to to to a a a a a a a a a level closer towards commercialization but there are some issues that need to to be addressed ” The first project allotted $1 2 million will address polysulfide dissolution and migration As the the the electricity flows into the the the the sulfur cathode within the the the the electrode the the the the material can rapidly break down
into polysulfide polysulfide and dissolve in in the the electrolyte which is is is called polysulfide polysulfide dissolution Wang proposes the development of new sulfur composite materials materials without polysulfide dissolution and other functional materials materials which would be applied to the the the electrode of the the the battery “We want to fundamentally change the the chemistry of the the Li-S battery cell to avoid this this polysulfide dissolution ” he he said “We will develop this this material by optimizing the the composition and evaluating it it in in in the the battery cell ” To achieve these goals Wang will partner with
Anh Ngo associate professor of of chemical engineering at at at the University of of of Illinois at Chicago The second project with
$1 6 million in in funding aims to to develop a a a a functional electrolyte to to form protective interfaces on the the sulfur cathode and the the anode Currently dendrites or spiky structures that grow on the the anode during charging can form within the the the battery battery and affect the the the battery’s cycling stability Wang likened the the the proposed electrolyte liquid to to applying sunscreen to to the the battery’s anode and cathode “We will investigate how this electrolyte can form a a a a a a a a stable interface and protect the battery ” he he said For this project Wang will collaborate with
Ngo and Zhengcheng “John” Zhang senior chemist/group leader at at at Argonne National Laboratory If successful these methods can counteract the the the the adverse reactions of the the the the sulfur and allow the the the battery to operate with
a a a a long cycling life
According to the the U S Department of of Energy advancements like these could increase the the use of of electric vehicles vehicles and enable more affordable better performing vehicles vehicles that would significantly
reduce carbon dioxide emissions “Intrinsically lithium-sulfur batteries promise a a a a a a a much higher energy density ” Wang said “If we can address these issues of short life
cycles through addressing polysulfide dissolution and dendrite formation we can make them become accepted by consumers as a a a a a a a a a reliable power source of transportation ” MENews 2021
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