Tech Insights

Longer Battery Life: Exploring Quantum Mechanics’ Potential for EVs

April 19, 2024 by Jake Hertz

Texas A&M University leveraged quantum mechanics to investigate how external pressure impacts the performance of lithium-metal batteries.

Lithium metal batteries are widely considered an alternative to lithium-ion batteries in electrical vehicles (EVs) thanks to their remarkable energy density and prolonged lifespans. However, the technology faces numerous challenges, including high anode reactivity, which poses performance constraints and safety risks. 

Researchers from Texas A&M University are attempting to enhance lithium metal battery fabrication processes by exploring their behavior under pressure. What exactly are the challenges with lithium metal batteries? And how is Texas A&M solving these issues? 

 

Lithium metal is an alternative to lithium-ion batteries.

Lithium metal is an alternative to lithium-ion batteries. Image used courtesy of Adobe Stock

 

Unveiling Challenges in Lithium-Ion

Lithium-ion batteries are widely used in renewable energy applications. However, their biggest issue is limited energy density. 

On the other hand, lithium metal batteries hold significant promise for energy storage technology due to their high energy density potential. Unlike conventional lithium-ion batteries, which rely on intercalation reactions, lithium metal batteries directly use metallic lithium as the anode, offering higher theoretical energy densities. This attribute makes them particularly attractive for applications requiring long-lasting power sources in compact spaces, such as EVs and grid-scale energy storage systems

However, lithium metal batteries also pose challenges, such as the uneven lithium plating linked to solid electrolyte interphase (SEI). SEI is a thin layer forming on the surface of lithium-ion battery electrodes. It’s crucial for battery stability and performance. 

 

Dendrite formation in a lithium-metal battery.

Dendrite formation in a lithium-metal battery. Image used courtesy of Idaho National Laboratory

 

An ideal SEI film should be electrically insulating and ionically conductive. Moreover, it should be chemically/mechanically stable to protect lithium metal from electrolyte exposure and accommodate volume changes. However, due to the uneven lithium metal surface, lithium ions tend to deposit preferentially at tips, leading to dendrite formation during stripping and plating cycles. These dendrites can penetrate the separator, which is meant to prevent electrical contact between the electrodes, causing internal short circuits. In severe cases, dendrite growth can result in thermal runaway, leading to battery overheating, fire, or even explosion. 

 

Lithium Metal Batteries Under Pressure?

Researchers from Texas A&M University developed an innovative method using quantum mechanics to understand the impact of external pressure on lithium metal batteries. Their research addressed improving lithium metal battery fabrication processes for longer-lasting and more efficient batteries.

Lithium metal batteries have anodes made of lithium metal rather than the graphite anodes used in conventional lithium-ion batteries. Theoretically, this substitution could increase energy density by a factor of 10. However, lithium metal's reactivity requires innovative control measures like external pressure application. External pressure alters the surface morphology of the lithium metal anode, affecting ion migration pathways and electrodeposition kinetics. 

 

Diagram showing the trajectories of lithium ions near the anode

Diagram showing the trajectories of lithium ions near the anode. Image used courtesy of Texas A&M

 

Through quantum mechanical analysis, the researchers discovered that pressure-induced lithium ions detour toward regions with higher pressure or lithium atom concentration on the anode surface. This behavior is caused by the electric field generated by the lithium metal anode. This discovery can effectively solve the problem of dendrite formation caused by uneven lithium-ion distribution. Moreover, understanding these effects allows for predicting ion behavior and optimizing battery fabrication processes to enhance battery performance, longevity, and safety.

The study found that improved lithium deposition and stripping behaviors in pressed cells lead to a 5% increase in Coulombic efficiency, reaching about 90%, and more than fivefold longer cycling life.

 

A Bright Future for Lithium Metal Batteries

With ongoing collaboration through the Battery500 Consortium, researchers continue efforts to advance reliable and high-performing vehicle batteries. The findings hold promise for future applications, potentially changing battery fabrication processes and extending battery life. As this research progresses, the widespread adoption of EVs draws closer.