The risks of high-nickel cathodes in EV batteries

Many consumers are concerned about the safety risks of EV batteries in accidents. To meet the demand for longer driving ranges, manufacturers are turning to high-nickel ternary alloys and manganese-based, lithium-rich metal oxides for lithium-ion battery (LiB) cathodes. These compounds offer significantly higher energy density and capacity at lower cost, making them a promising solution for advanced EV battery packs.

However, these materials have lower thermal stability under high-heat and high-voltage conditions, leading to oxygen release (and electrolyte combustion), metal ion dissolution and HF formation under such conditions. This leads to capacity loss upon cycling and increases the risk of thermal runaway, potentially causing fires or explosions—issues that not only result in costly recalls but also damage an automotive brand's reputation.

In response, some EV producers have adopted cobalt-free lithium iron phosphate (LFP) batteries for their enhanced safety and cost efficiency. However, their lower energy density requires more cells to achieve comparable driving ranges, adding weight and complexity.

How Stanyl® SN-PURE optimizes battery safety and performance

Envalior’s Stanyl® SN-PURE, succinonitrile (SN), is a revolutionary electrolyte additive that enhances the safety and reliability of LiBs by forming a sub-nanometer thick protective layer at the cathode. Its key benefits include:

• High purity (99.95%): Ensures optimal battery performance with minimal impurities and no negative effect on the internal resistance of the battery. No subsequent purification needed.
• Thermal stability: SN can help raise temperature stability of LCO and NMC-type cathodes in presence of carbonate electrolytes. Shifting the onset themperature of extothermic reactions due to electrolyte decomposition by about 60°C higher, increasing thermal safety.
• Reduces heat evolution: Reduction of heat evolution by about one third in Thermal runaway SN blocks or suppresses thermally accelerated side reactions between cathode and electrolyte.
• Oxidation Resistance: SN layer on the cathode reduces oxygen release from the cathode and, thus, the electrolyte decomposition and gas formation. 
• Improves cyclability and capacity Retention: The SN layer on the cathode helps to stabilize the electrolyte allowing it to be used at higher voltages.
• Regulatory compliance: Meets global safety standards for battery manufacturing.
• Global availability: Produced at scale to mitigate supply chain risks.

Ensuring safe and reliable battery packs

Extensive testing with ethylene carbonate (EC)-based electrolytes and lithium cobalt oxide (LCO) and Nickel Manganese Cobalt (NMC) cathodes highlights the critical role of SN additives in improving battery safety and performance.

Electrolytes enhanced with SN additives effectively prevent thermal runaway, remaining stable even when battery chambers are heated to 150°C. In contrast, additive-free versions became unstable after 40 minutes, triggering rapid and dangerous temperature increases. Oxidation stability testing revealed that SN additives reduce gas expansion by over 50% during 70 minutes of high-heat exposure. Additionally, batteries containing SN additives maintained consistent capacity after >1000 charging cycles.

Extending use of  Stanyl® SN-PURE beyond LiB to sodium ion batteries (SiB)

Due to high demand of LiB batteries (SiB) and challenging supply availability of Lithium, industries outside of electric vehicles are looking into alternative battery technologies. Sodium Ion Batteries are recently receiving increasing attention as a promising alternative for LiB, raising interest in several market segments including energy storage solutions, grid stabilization, or in some mobility solutions. 

Key benefits Stanyl® SN-PURE shown in SiB

• Increase electrolyte stability: SN inhibits decomposition of carbonate and nitrile based solvents at high voltages. This leads to improved capacity retention and, thus, extending cycling life. 

Mitigating supply chain challenges

We understand the importance of reliable material supplies for battery manufacturing. Shortages or limited availability can disrupt production timelines, particularly as demand grows for LiB components in Europe and the Americas. SN has been produced in Europe uninterrupted during more than 30 years, hence the influence of geopolitical risks on supply chain are  vastly reduced.

Envalior’s global footprint, with offices and production facilities in all major markets, ensures access to regionally independent supplies of high-performance material additives. This commitment to supply chain resilience supports the rapid growth of emerging LiB manufacturing industries.

Even during the COVID-19 pandemic, Envalior declared zero force majeures, maintaining uninterrupted supply to meet our customers’ evolving needs. This proactive approach enables us to help you deliver safe, high-performance EV battery packs, accelerating the transition to clean energy transportation worldwide.

Transform your battery designs with safer, more efficient materials. Envalior’s Stanyl® SN-PURE ensures long-lasting, reliable battery performance, enabling manufacturers to drive the future of clean transportation.

Contact us today to explore how our solutions can optimize your battery systems.