Nickel is stepping into the spotlight as a key player in the world of electric vehicle (EV) batteries. As a more plentiful and easily sourced alternative to cobalt, nickel offers a higher energy density, which means longer driving ranges for EVs. But, as with anything promising, there are challenges. Concerns about nickel’s cycle life, thermal stability, and safety have kept its potential somewhat in check.
Researchers at The University of Texas at Austin and Argonne National Laboratory are tackling these issues head-on. They’re focusing on nickel-based cathodes, which are essential components in the energy storage systems of EV batteries. According to Arumugam Manthiram, a professor at the Walker Department of Mechanical Engineering and Texas Materials Institute, “High-nickel cathodes have the potential to revolutionize the EV market by providing longer driving ranges.” Their research, published in Nature Energy, dives deep into the thermal stability of these cathodes, a crucial factor for developing safer EV batteries.
In a thorough study involving over 500 measurements across 15 high-nickel cathode materials, researchers pinpointed a critical state of charge where the material becomes unstable. This instability can trigger thermal runaway, a dangerous condition where rising temperatures release energy that further heats the EV battery, increasing the risk of failure and potential fires.
The study also introduced a thermal stability index to measure how materials react during thermal runaway. Factors like composition, surface chemistry, nickel content, and crystal size play a big role in cathode stability.
The implications of this research are significant. It sets the stage for safer, more efficient batteries that can meet the growing demand for EVs. As the world shifts towards cleaner energy, these advancements are crucial for making EVs more appealing to consumers.
Zehao Cui, a research associate in Manthiram’s group, emphasized, “Our work provides a roadmap for the industry to follow, ensuring that the high energy density of these cathodes does not come at the cost of safety.” Looking ahead, researchers plan to integrate electrolytes into their work on thermal stability. These components, usually liquid-based, are essential for the battery’s charge and discharge functions, facilitating reliable interactions between electrolytes and cathodes. This step is vital for enhancing the safety and performance of electric vehicle batteries.
