China’s solid-state EV battery breakthrough shows stable performance over 1,200 hours
The alloy’s effectiveness stems from its low eutectic point and high lithium solubility.
Researchers at China’s Huazhong University of Science and Technology have announced a solution to a long-standing challenge hindering the commercialization of all-solid-state lithium metal batteries.
The team has created a novel mixed ion-electron conducting (MIEC) LixAg alloy anode that stabilizes the critical interface between lithium metal and garnet-type solid electrolytes, which could lead to safer, higher-energy-density batteries.
The researchers in a press release, said:
The technology could enable the next generation of electric vehicles with longer ranges, faster charging capabilities, and enhanced safety profiles,
Addressing the instability issue
The unstable interface between lithium metal anodes and solid electrolytes, particularly materials like Li6.5La3Zr1.5Ta0.6O12 (LLZTO), has been a major bottleneck for years.
This instability leads to poor lithium diffusion and the formation of lithium dendrites, which can cause short circuits and limit battery life.
The researchers, explain:
What makes this approach revolutionary is how it fundamentally changes lithium ion movement at the critical interface,
“The LixAg alloy creates a pathway for lithium ions that dramatically enhances diffusion kinetics, preventing the concentration gradients that typically lead to dendrite formation and interface degradation.”
Symmetric cells utilizing the LixAg alloy exhibited exceptional stability for approximately 1,200 hours at a current density of 0.2 mA/cm². This performance surpassed that of conventional lithium metal anodes.
Furthermore, the interfacial resistance between the LLZTO electrolyte and the LixAg anode was measured at an ultralow 2.5 Ω·cm², which indicates highly efficient ion transport across the interface.
The press release,
This dramatic reduction in interfacial resistance enables both higher power output and improved energy efficiency,
‘Soft lattice’ for sustained diffusion
The researchers attribute the LixAg alloy’s success to its unique physical properties, including a low eutectic point and high mutual solubility with lithium.
The researchers, remarked:
These characteristics create a ‘soft lattice’ that maintains high lithium diffusion rates even as the composition changes during battery cycling,
The team noticed that lithium stripping and plating preferentially occurred during battery cycling at the interface between the LixAg alloy and the current collector rather than at the delicate LLZTO/LixAg interface.
The press release, highlighted:
This phenomenon effectively protects the critical electrolyte-anode interface from contact loss during cycling, a common failure mechanism in solid-state batteries,
Excellent cycling stability, rate performance
To demonstrate the practical potential of their innovation, the researchers constructed full cells using LiFePO4 cathodes, LLZTO electrolytes, and LixAg anodes.
These cells exhibited excellent cycling stability and rate performance and confirmed the viability of this approach for real-world applications.
The research team suggests their findings offer a valuable guide for selecting other alloy phases for anode materials in garnet-based solid-state batteries.
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The team, Concluded:
Alloys with low eutectic temperatures and high mutual solubility with lithium should be prioritized in future research efforts,
“By solving the interface stability issue while enhancing lithium diffusion kinetics, the LixAg alloy anode brings us one step closer to a future where solid-state batteries power everything from smartphones to electric vehicles with unprecedented energy density and safety.”
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