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From the Lab to the Road: Stellantis Testing Li-S Batteries

June 07, 2024 by Jake Hertz

Lyten has delivered lithium-sulfur batteries to Stellantis and various U.S. and EU OEMs for evaluation.

As technological advancements drive the demand for energy storage, conventional lithium-ion batteries face significant hurdles. These include limited energy density, high production costs, and safety risks. Additionally, the reliance on scarce and expensive raw materials such as cobalt and nickel exacerbates supply chain issues and environmental impact. 

Lyten is manufacturing one alternative, lithium-sulfur (Li-S) batteries, for electric vehicles (EVs). The company will send EV manufacturer Stellantis Li-S pouch batteries for testing and evaluation.

 

EV batteries

EV batteries. Image used courtesy of Lyten

 

Lithium-Ion’s Underlying Challenges

Lithium-ion batteries face a plethora of technical, environmental, and geopolitical challenges. They rely on geographically concentrated and limited resources like lithium, cobalt, and nickel, raising concerns about long-term availability and geopolitical risks. As demand grows, maintaining a stable supply chain becomes increasingly difficult. Despite being more environmentally friendly than fossil fuels, lithium-ion batteries still pose environmental challenges, including habitat destruction, water pollution, and carbon emissions during extraction, processing, and disposal

 

Lithium mine in Australia

Lithium mine in Australia. Image used courtesy of Wikimedia Commons

 

From a technical perspective, lithium-ion batteries are limited in terms of theoretical energy density and face safety issues like thermal runaway, which can cause fires or explosions. These limitations of lithium-ion batteries stem from their internal structure and chemistry. Limited energy density is intrinsic to electrode materials and design, constrained by factors like electrode thickness and active material choice. For example, graphite, commonly used as the anode material, presents challenges due to its low specific capacity and susceptibility to dendrite formation, risking short circuits and compromising safety. 

Thermal runaway results from the electrolyte's instability, causing decomposition at high temperatures and leading to flammable gas release and catastrophic failure. Addressing these limitations requires advancements in electrolyte stability, electrode materials, and battery design.

 

Lithium-Sulfur and Graphene

In a major development for battery chemistries, Stellantis and other leading U.S. and European automakers are poised to test Lyten’s inaugural production line of Li-S batteries. 

Lyten, a supermaterial pioneer, has shipped A samples of its 6.5 Ah Li-S pouch cells for commercial evaluation. Operating from an automated pilot production line in San Jose, California, Lyten utilized standard lithium-ion manufacturing equipment to produce Li-S batteries. These batteries feature a lithium metal anode and a sulfur cathode, facilitating the migration of lithium ions during discharge to form lithium sulfide. 

Since the early 1960s, Li-S batteries have emerged as a promising storage system due to sulfur's abundant and low-cost nature. They offer high theoretical gravimetric and volumetric capacity alongside a remarkable energy density of 1672 mAh g−1.  

 

Comparing energy densities of various batteries

Comparing energy densities of various batteries. Image used courtesy of Lyten

 

By integrating a proprietary 3D graphene structure into the cathode, Lyten enhanced stability and conductivity, mitigating issues like the polysulfide shuttle effect. Lyten's 3D graphene offers unparalleled resistive, capacitive, inductive, structural, and energy-absorbing properties. Derived from greenhouse gases, it transforms carbon into a solid 3D graphene. This tunable material can be engineered at the atomic level to optimize thermal and electrical properties, enhance strength, reduce weight, and more.

Additionally, employing a lithium metal composite for the anode improves stability, efficiency, and energy density while eliminating the need for critical minerals like nickel, cobalt, and manganese in the cathode. This innovation resulted in a projected 65% lower carbon footprint than lithium-ion batteries.  

 

Powering the Future

In addition to Stellantis, Chrysler integrated lithium-sulfur batteries into its Halcyon concept EV in February 2024. Lyten has been operating a pilot production line since May 2023 and plans to ship cylindrical A sample batteries later in 2024. The company is also preparing to build its first giga-scale factory, backed by a $4 million grant from the US Department of Energy.