Tech Briefs Magazine - February 2024 - 37

A New Design for Lithium-Sulfur Batteries
The design can reduce shuttling within the battery and increase its capacity to hold more
charge as well as last for more cycles.
Argonne National Laboratory, Lemont, IL
W
hile lithium-ion (Li-ion) batteries have come a long way
since they were first introduced, they have some familiar
drawbacks as well, such as short lifetimes, overheating and supply
chain challenges for certain raw materials. Scientists at the U.S.
Department of Energy's (DOE) Argonne National Laboratory
are researching solutions to these issues by testing new materials
in battery construction. One such material is sulfur. Sulfur is extremely
abundant and cost effective and can hold more energy
than traditional ion-based batteries.
In a new study, researchers advanced sulfur-based battery research
by creating a layer within the battery that adds energy storage
capacity while nearly eliminating a traditional problem with
sulfur batteries that caused corrosion.
A promising battery design pairs a sulfur-containing positive
electrode (cathode) with a lithium metal negative electrode (anode).
In between those components is the electrolyte, or the substance
that allows ions to pass between the two ends of the battery.
Early lithium-sulfur (Li-S) batteries did not perform well because
sulfur species (polysulfides) dissolved into the electrolyte,
causing its corrosion. This polysulfide shuttling effect negatively
impacts battery life and lowers the number of times the battery
can be recharged.
To prevent this polysulfide shuttling, previous researchers
tried placing a redox-inactive interlayer between the cathode
and anode. The term " redox-inactive " means the material does
not undergo reactions like those in an electrode. But this protective
interlayer is heavy and dense, reducing energy storage
capacity per unit weight for the battery. It also does not reduce
shuttling. This has proved a major barrier to the commercialization
of Li-S batteries.
To address this, researchers developed and tested a porous sulfur-containing
interlayer. Tests in the laboratory showed initial
capacity about three times higher in Li-S cells with this active, as
opposed to inactive, interlayer. More impressively, the cells with
the active interlayer maintained high capacity over 700 charge-discharge
cycles.
" Previous experiments with cells having the redox-inactive layer
only suppressed the shuttling, but in doing so, they sacrificed
the energy for a given cell weight because the layer added extra
weight, " said Guiliang Xu, an Argonne Chemist and co-author of
the paper. " By contrast, our redox-active layer adds to energy storage
capacity and suppresses the shuttle effect. "
To further study the redox-active layer, the team conducted experiments
at the 17-BM beamline of Argonne's Advanced Photon
Source (APS), a DOE Office of Science user facility. The data
gathered from exposing cells with this layer to X-ray beams allowed
the team to ascertain the interlayer's benefits.
The data confirmed that a redox-active interlayer can reduce
shuttling, reduce detrimental reactions within the battery and increase
the battery's capacity to hold more charge and last for
more cycles. " These results demonstrate that a redox-active interlayer
could have a huge impact on Li-S battery development, "
said Wenqian Xu, a beamline scientist at APS. " We're one step
closer to seeing this technology in our everyday lives. "
Going forward, the team wants to evaluate the growth potential
of the redox-active interlayer technology. " We want to try to
make it much thinner, much lighter, " Guiliang Xu said.
For more information, contact Christopher Kramer at
media@anl.gov; 630-252-5580.
53 um
50 um Si
O
S
Image shows microstructure and elemental mapping (silicon, oxygen, and
sulfur) of porous sulfur-containing interlayer after 500 charge-discharge cycles
in lithium-sulfur cell. (Image: Guiliang Xu/Argonne National Laboratory)
Tech Briefs, February 2024
www.techbriefs.com
37
http://info.hotims.com/86252-771 http://www.techbriefs.com
Tech Briefs Magazine - February 2024

Table of Contents for the Digital Edition of Tech Briefs Magazine - February 2024
