Protective dual shell unlocks longer-lasting lithium-rich batteries

The global demand for high-energy lithium-ion batteries is rising, driven by the push for electric vehicles and renewable energy storage. Lithium-rich layered oxides (LRMO) stand out because of their high theoretical capacity and cost advantages. Yet despite their promise, they face critical setbacks: oxygen release at high voltages, severe structural transformations, and interfacial corrosion triggered by electrolyte decomposition. These processes not only erode the electrode surface but also lead to transition metal loss and voltage decay. Many surface coating strategies have been explored, yet they often fall short by impeding ion transport or peeling away during cycling. Due to these challenges, there is an urgent need to engineer more effective surface protections for lithium-rich cathodes.

In a study (DOI: 10.26599/EMD.2025.9370065) published on June 19, 2025, in Energy Materials and Devices, a research team from Hebei University and Longyan University unveiled a novel LiF@spinel dual-shell coating for lithium-rich cathodes. This breakthrough design unites the benefits of two protective layers: a spinel buffer that enables fast lithium-ion diffusion and a LiF layer chemically bonded to guard against corrosive attack. The result is a stable and durable electrode that resists interfacial degradation, offering a practical way to unlock the long-envisioned potential of high-capacity lithium-rich batteries.

The team’s approach centered on building a two-part shield around the LRMO cathode. Using an in situ reconstruction process, a spinel intermediate layer was grown directly on the cathode surface. This spinel provides a three-dimensional framework for lithium-ion transport, ensuring that high capacities can be accessed quickly. The outer LiF coating, chemically anchored by Ni–F bonds, firmly attaches to the spinel and isolates the electrode from harmful electrolytes. Advanced tools such as transmission electron microscopy and X-ray photoelectron spectroscopy confirmed the seamless integration of the dual shell. The performance gains were striking: at a demanding current of 2 C, the protected cathode retained 81.5% of its capacity after 150 cycles, compared to only 63.2% for its unmodified counterpart. Even under ultrafast cycling at 5 C, the dual-shell design maintained more than 80% capacity. Electrochemical impedance tests further revealed lower resistance and higher ion diffusion rates, while post-cycle surface analyses showed fewer corrosive by-products and greater structural stability. Taken together, the results highlight how the LiF@spinel strategy addresses both chemical degradation and ion-transport limitations, delivering a balanced solution for high-energy lithium-ion batteries.

 “The dual-shell LiF@spinel architecture provides a new paradigm for stabilizing lithium-rich cathodes,” said Prof. Chaochao Fu, corresponding author of the study. “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.”

The implications of this breakthrough extend far beyond the laboratory. Enhancing the durability of lithium-rich cathodes could accelerate the deployment of electric vehicles with longer ranges, expand the lifetime of portable electronics, and improve the efficiency of renewable energy storage systems. Importantly, the dual-shell design offers a blueprint that can be adapted to other unstable electrode materials, paving the way for broader advances in energy storage. By overcoming long-standing barriers to stability and performance, the LiF@spinel approach could play a pivotal role in shaping the future of sustainable power technologies.

Funding information

This work is funded by Science Research Project of Hebei Education Department (Grant No. ZD2022042), the Interdisciplinary Research Program of Hebei University (Grant No. DXK202315), the National Natural Science Foundation of China (NSFC) (Grant Nos. 52104304 and 51902081), Central Government Guided Local Science and Technology Development Project of Hebei Province (Grant No. 246Z4409G), and the Scientific Research and Innovation Team of Hebei University (Grant No. IT2023B07).

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