Reviewed by Frances BriggsSep 1 2025
A research team at Hebei University and Longyan University has introduced a promising LiF@spinel dual-shell coating for lithium-rich cathodes, published in Energy Materials and Devices.
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Global demand for high-energy lithium-ion batteries is increasing in line with electric vehicle and renewable energy storage production. Among the most promising candidates are lithium-rich layered oxides, which offer both high theoretical capacity and cost efficiency. However, their commercial viability is limited by a few critical issues, such as oxygen release at high voltages, structural instability, and interfacial corrosion from electrolyte breakdown.
These processes degrade the electrode surface while also causing transition metal loss and voltage degradation. Many surface coating techniques have been tested; however, they frequently fail by blocking ion transport or peeling away during cycling. As a result, there is a pressing need to develop more effective surface protections for lithium-rich cathodes.
The newly published design combines the advantages of two protective layers: a spinel buffer for rapid lithium-ion diffusion and a LiF layer chemically bonded to defend against corrosive assault. The end result is a highly stable cathode structure that resists interfacial deterioration, providing a realistic approach to realizing the long-anticipated potential of high-capacity lithium-rich batteries.
The key strategy in the team's research was to build a two-part shield around the LRMO cathode. The spinel intermediate layer was generated directly on the cathode surface using an in situ rebuilding technique. This spinel allows rapid access to large capacities by offering a three-dimensional framework for lithium-ion transport. The outer LiF covering securely adheres to the spinel and keeps the electrode safe from dangerous electrolytes, thanks to its chemical anchoring provided by Ni–F bonds.
Advanced technologies, including transmission electron microscopy and X-ray photoelectron spectroscopy, demonstrated that the dual shell was seamlessly integrated. The performance improvements were significant: at a high current of 2 C, the shielded cathode preserved 81.5 % of its capacity after 150 cycles, compared to just 63.2 % for its unmodified counterpart. Even after rapid cycling at 5 °C, the dual-shell design retained more than 80 % capacity.
Electrochemical impedance tests revealed even more reduced resistance and faster ion diffusion rates, while post-cycle surface investigations demonstrated less corrosive byproducts and enhanced structural integrity.
Taken together, the findings demonstrate how the LiF@spinel technique tackles both chemical degradation and ion-transport restrictions, forming a well-balanced solution for high-energy lithium-ion batteries.
By coupling the rapid ion transport of spinel with the protective barrier of LiF, we’ve created a synergistic defense that prevents surface collapse and extends cycle life. This innovation not only boosts the practical performance of lithium-rich materials but also offers valuable design insights for engineering other next-generation electrode systems.
It is an encouraging step toward making high-capacity batteries truly viable for widespread use.
Chaochao Fu, Study Corresponding Author and Professor, Hebei University
This innovation could have far-reaching consequences outside of the laboratory. Improving the endurance of lithium-rich cathodes could accelerate the adoption of longer-range electric cars, extend the life of portable gadgets, and boost the efficiency of renewable energy storage systems.
The dual-shell design provides a blueprint that can be applied to other unstable electrode materials, which could allow for significant breakthroughs in energy storage and sustainable power.
Journal Reference:
Fu, C., et al. (2025) Constructing LiF@spinel dual shell to suppress interfacial side reactions of Li-rich cathode materials. Energy Materials and Devices. doi.org/10.26599/EMD.2025.9370065.