A multi-institutional research team led by Georgia Tech‘s Hailong Chen has developed a new, low-cost cathode that could potentially revolutionize lithium-ion batteries (LIBs), with the potential to significantly impact the electric vehicle (EV) market and large-scale energy storage systems.
“For a long time, people have been looking for a lower-cost, more sustainable alternative to existing cathode materials. I think we’ve got one,” said Chen, an associate professor with appointments in the George W. Woodruff School of Mechanical Engineering and the School of Materials Science and Engineering.
The newly developed cathode material, iron chloride (FeCl3), has the potential to be a game-changer. It costs a mere 1-2% of typical cathode materials and offers the same energy storage capacity. Cathode materials play a crucial role in a battery’s performance, lifespan, and cost, and this innovation could significantly improve the EV market and the entire lithium-ion battery market.
“Our cathode can be a game-changer,” said Chen, whose team describes its work in Nature Sustainability. “It would greatly improve the EV market — and the whole lithium-ion battery market.”
First introduced by Sony in the early 1990s, lithium-ion batteries (LIBs) revolutionized personal electronics, propelling the rapid growth of smartphones and tablets. This technology later evolved to power electric vehicles, offering a dependable, rechargeable, high-energy storage solution. However, the cost of LIBs has been a significant factor, particularly for large-scale energy consumers like EVs.
Currently, batteries account for approximately 50% of an electric vehicle’s total cost, making these eco-friendly cars more expensive than traditional internal combustion vehicles. The groundbreaking innovation from the Chen team has the potential to disrupt this status quo.
Compared to traditional alkaline and lead-acid batteries, lithium-ion batteries (LIBs) pack more power into a smaller size, providing longer-lasting energy for devices. However, LIBs are often made with costly metals like cobalt and nickel, leading to high manufacturing expenses.
While only four types of cathodes have been successfully commercialized for LIBs, Chen’s innovation could revolutionize battery technology with the development of an all-solid-state LIB.
Unlike conventional LIBs which use liquid electrolytes and have limitations on energy storage, as well as safety concerns, all-solid-state LIBs employ solid electrolytes, significantly enhancing efficiency, reliability, and safety while enabling higher energy capacity. These next-generation batteries, still undergoing testing and development, promise a substantial leap forward in energy storage technology.
In a global race to make all-solid-state technology viable, Chen and his team have devised an affordable and sustainable solution. Their FeCl3 cathode, solid electrolyte, and lithium metal anode have slashed the cost of the entire battery system to just 30-40% of current LIBs.
“This could not only make EVs much cheaper than internal combustion cars, but it provides a new and promising form of large-scale energy storage, enhancing the resilience of the electrical grid,” Chen said. “In addition, our cathode would greatly improve the sustainability and supply chain stability of the EV market.”
Chen’s fascination with FeCl3 as a cathode material stemmed from his lab’s exploration of solid electrolyte materials. Commencing in 2019, his team endeavored to develop solid-state batteries using chloride-based solid electrolytes paired with conventional commercial oxide-based cathodes. However, the combination proved to be incompatible, resulting in subpar performance.
Recognizing the potential for a chloride-based cathode to form a more harmonious partnership with the chloride electrolyte and thereby enhance battery performance, the researchers sought out a promising candidate.
“We found a candidate (FeCl3) worth trying, as its crystal structure is potentially suitable for storing and transporting Li ions, and fortunately, it functioned as we expected,” said Chen.
The current dominant cathodes in electric vehicles rely on oxides and demand a significant amount of expensive nickel and cobalt, both of which are heavy elements that can be toxic and present environmental challenges. In contrast, the cathode developed by the Chen team consists of only iron (Fe) and chlorine (Cl) — abundant, affordable, widely used elements found in steel and table salt.
During initial tests, FeCl3 demonstrated performance equal to or better than other, much more costly cathodes. For instance, it boasts a higher operational voltage than the widely used cathode LiFePO4 (lithium iron phosphate, or LFP), which is analogous to the electrical force a battery delivers when connected to a device, akin to water pressure from a garden hose.
This breakthrough technology could potentially be commercially viable for electric vehicles in less than five years. The team is committed to further exploring FeCl3 and related materials. This research was spearheaded by Chen and postdoc Zhantao Liu, the lead author of the study. Collaborators included researchers from Georgia Tech’s Woodruff School (Ting Zhu) and the School of Earth and Atmospheric Sciences (Yuanzhi Tang), as well as the Oak Ridge National Laboratory (Jue Liu) and the University of Houston (Shuo Chen).
“We want to make the materials as perfect as possible in the lab and understand the underlying functioning mechanisms,” Chen said. “But we are open to opportunities to scale up the technology and push it toward commercial applications.”
Journal reference:
- Zhantao Liu, Jue Liu, Simin Zhao, Sangni Xun, Paul Byaruhanga, Shuo Chen, Yuanzhi Tang, Ting Zhu & Hailong Chen. Low-cost iron trichloride cathode for all-solid-state lithium-ion batteries. Nature Sustainability, 2024; DOI: 10.1038/s41893-024-01431-6