Lithium-sulfur (Li-S)
batteries have some chance of replacing lithium-ion batteries for two reasons:
higher gravimetric energy density and lower cost. They have been around since
the 1960s but new developments have made them more viable. However, there are
other problems to be worked out, including degradation or cycle life. Li-S
batteries use sulfur, which is less expensive than the iron and cobalt used in
lithium-ion batteries. Sulfur is also lighter. They use metallic lithium rather
than lithium ions which improves the energy density. According to Wikipedia: “Li–S
batteries offer specific energies on the order of 550 Wh/kg, while lithium-ion
batteries are in the range of 150–260 Wh/kg.” No Li-S batteries were
available on the market by early 2021, but they are just about to be
commercialized en masse. The major issue with Li-S batteries has been the
polysulfide "shuttle" effect that causes progressive leakage of
active material from the cathode, resulting in too few recharge cycles. This
problem has recently been overcome. Zeta Energy announced in 2023 that several laboratories
have confirmed that their Li-S batteries with sulfurized-carbon cathodes were
polysulfide shuttle-free. Previous attempts to commercialize Li-S batteries,
mostly in the late 2010s, have failed. However, that is about to change as gigafactory
manufacturing is set to happen in Nevada.
Li-S battery showing polysulfide shuttling effect. Source: Wikipedia
Li-S batteries are considered to be semi-solid
state or solid state. One advantage of solid-state batteries is that there is
no chance of fires as there is with liquid lithium-ion batteries. Li-S batteries are lighter, cheaper, energy-denser, and safer, but not as durable but that is changing as you will see.
New Developments in Li-S Batteries: Iodine, Polymer
Coatings, a Polyacrylic Acid Layer, and Nanotechnology
In March 2024 Interesting
Engineering reported on a new healable cathode:
“A group of engineers at the University of California,
San Diego, have created a new cathode material for solid-state lithium-sulfur
batteries. The new material is electrically conductive and structurally
healable, thus overcoming the drawbacks of the existing cathodes in these
batteries.”
“Researchers claimed they significantly enhanced the
cathode material’s electrical conductivity by 11 orders of magnitude by
introducing iodine molecules into the crystalline sulfur structure, making it
100 billion times more conductive than sulfur crystals alone.”
“This sulfur-iodide cathode presents a unique concept for
managing some of the main impediments to the commercialization of Li-S
batteries. Iodine disrupts the intermolecular bonds holding sulfur molecules
together by just the right amount to lower its melting point to the Goldilocks
zone—above room temperature yet low enough for the cathode to be periodically
re-healed via melting,” said Shyue Ping Ong, study co-senior author and a
professor of nanoengineering at the UC San Diego Jacobs School of Engineering.”
Testing revealed that
the battery was still at 87% capacity after 400 charging cycles. That would
represent about 100,000 miles for an EV with a range of 250 miles. Good but not
good enough. The self-healing that occurs simply by heating it up could be
incorporated into Li-S batteries of the future.
An Interesting Engineering
article from September 2024 gives another new development from Chinese
scientists and engineers:
However, the adoption of Li-S batteries is limited. “The
main challenges preventing the widespread adoption of Li-S batteries are their
short cycling life, low-rate performance and safety concern via using lithium
metal as an anode,” Liping Wang, a professor of Material Science and
Engineering at the University of Electronic Science and Technology in China
told Interesting Engineering in an email.
The Chinese researchers found that a layer
of polyacrylic acid (PAA) as effective in reducing the polysulfide shuttling
effect. The layer retained its charging capacity at 72% after 300 cycles. That
does not seem impressive to me, at least for an EV, unless the batteries are
very cheap, and disposable in the sense of having a short lifetime. This affects overall
lifetime costs too. They noted that the PAA layer could have applications with
other battery chemistries, including lithium-molybdenum and lithium-vanadium
batteries.
Interesting
Engineering also reported on a new Li-S battery in an article from October 2023
that uses a nanoporous polymer-coated lithium foil anode. The design uses less
lithium per component which reduces costs. The designers noted that it “uses
significantly less lithium, generates more energy per volume, lasts far longer,
and will cost half as much as current lithium-ion batteries.” The polymer
is able to selectively filter the small lithium ions. It also helps it charge
and discharge repeatedly by acting as a “scaffold,” the researchers noted. The
abstract to the paper in Advanced Sustainable Systems explains:
“Lithium metal batteries, in particular lithium–sulfur
chemistries, hold great promise in energy storage from potentially increased
gravimetric storage density and diminished reliance on transition metals,
lowering resource demand and hence overall unit cost. However, these cells can
have their feasibility improved to a greater extent by lowering the demand for
lithium within their construction and reducing the polysulfide shuttling effect.”
Hot off the
press, a new Li-S breakthrough was just announced after I started writing this
post. The press release below is from the Australian company Li-S Energy, Ltd.
Li-S Energy has announced a major advancement in
lithium-sulfur battery technology, achieving an impressive 498Wh/kg energy
density with their new 10Ah semi-solid-state cells. This breakthrough is poised
to enhance drone, defense, and electric aviation markets by improving range and
payload capacities. The company’s innovative approach places it at the
forefront of the industry, drawing significant attention from global sectors.
The breakthrough
involves the use of Boron Nitride Nanotubes (BNNTs), and a new nano-composite
that aids strength, increases life cycle, and improves performance of the
cells. Li-S Energy, Ltd. Is partnered with an Australian manufacturer of BNNTs,
which have not been used in batteries up to now because of cost and lack of
manufacturing.
What Will the Future Be For Li-S Batteries? If Challenges
Can Continue to Be Overcome It Could Make E-Power Cheaper, Lighter, Safer, and
More Durable
With several
different technologies successfully addressing the challenges of Li-S batteries
it will be interesting to see which ones compete the best in terms of cost and
performance. Maybe multiple breakthroughs can be combined. One thing for
certain is that R&D is ongoing. As can be seen below from the description
of Lyten’s Li-S battery, nanocomposites and protective coatings will both
be utilized in the same design.
Lyten Plans to Build the World’s First Li-S Gigafactory
Near Reno, Nevada
Supermaterials
company Lyten has been manufacturing battery components at its plant in
California. It was announced in October 2024 that it will build a Li-S gigafactory
in Nevada, near Reno.
“It will manufacture cathode active materials and lithium
metal anodes and assemble lithium-sulfur cells, enabling a 100% domestically
manufactured battery, according to a press release by the company.”
“At its maximum the facility will have the capability to
produce up to 10 GWh of batteries annually.”
The planned 1,25
million square foot facility is expected to be built on the 125-acre campus of
Reno AirLogistics Park. The project is expected to be fully compliant with the
Inflation Reduction Act by sourcing all materials domestically, including
lithium. The gigafactory is expected to come online by 2027. Lyten expects
their batteries to be used in many applications as noted on their website:
“Lyten has begun the multi-year qualification process for
EVs, Trucks, Delivery Vehicles, and Aviation. But, Lyten is also on target to
deliver commercial ready batteries for Drones, Satellites, and Defense
applications in 2024 and micromobility and mobile equipment in 2025.”
Stellantis CEO Carlos Tavares had this to say about Lyten’s
Li-S battery potential for EVs:
“Specifically, Lyten’s Lithium-Sulfur battery has the
potential to be a key ingredient in enabling mass-market EV adoption globally,
and their material technology is equally well-positioned to help reduce vehicle
weight, which is all necessary for our industry to achieve carbon net zero
goals.”
Source: Lyten (website)
Lyten's Li-S Battery
According to its website the Lyten Li-S battery uses both nanomaterials (3D graphene) to mitigate polysulfide shuffling and protective anode coating to mitigate anode degradation. The company also notes that their San Jose, California factory was a converted lithium-ion factory which they converted at very low cost and noted that it can be done in the future as well if Li-S tech is proved up commercially. Lyten's battery architecture and cathode/anode weight requirements from their website are shown below.
Lyten thinks that
the costs for Li-S batteries will drop by 20% from 2025 to 2030 and be able to outcompete
both lithium-iron-phosphate and nickel-cadmium batteries as the graph below
shows.
References:
World’s
first lithium-sulfur gigafactory to produce 10 GWh batteries yearly. Abhishek
Bhardwaj. Interesting Engineering. October 16, 2024. World’s first lithium-sulfur
gigafactory to produce 10 GWh batteries yearly (msn.com)
China
builds unstoppable Li-S battery that works even after being cut in half. Ameya
Peleja. Interesting Engineering. September 13, 2024. China
creates Li-S battery that works even after being cut in half
Healable
cathode to advance solid-state lithium-sulfur batteries. Jijo Malayil.
Interesting Engineering. March 6, 2024. Healable
cathode to advance solid-state lithium-sulfur batteries
Lithium-sulfur
battery. Wikipedia. Lithium–sulfur
battery - Wikipedia
Li-S
Energy Unveils Breakthrough in Lithium-Sulfur Technology. TipRanks Australian
Auto-Generated Newsdesk. October 27, 2024. Li-S
Energy Unveils Breakthrough in Lithium-Sulfur Technology
Lighter
lithium-sulphur batteries offer significantly lower costs. Loukia Papadopoulos.
Interesting Engineering. October 24, 2023. Lighter
lithium-sulphur batteries offer significantly lower costs
A
Nanoporous Permselective Polymer Coating for Practical Low N/P Ratio Lithium
Metal Batteries. Declan McNamara, Mahdokht Shaibani, Mainak Majumder, and Matthew
R. Hill. September 4, 2023. Advanced Sustainable Systems. A
Nanoporous Permselective Polymer Coating for Practical Low N/P Ratio Lithium
Metal Batteries - McNamara - 2023 - Advanced Sustainable Systems - Wiley Online
Library
BNNT —
the game-changing nano material. Li-S Energy (website). Technology - Li-S Energy
Lithium-Sulfur
Batteries. Lyten (website). Lithium-Sulfur
Batteries - Battery Lithium-Sulfur | Electric Vehicles | Lyten 3D Graphene™
Supermaterials
No comments:
Post a Comment