Metal halide perovskite greatly improves the cycle stability of lithium batteries

The reporter learned from the University of Science and Technology of China on the 14th that the team of Yao Hongbin of the School of Nuclear Chemistry and Materials Science and Technology collaborated with collaborators to fully utilize the advantages of the wide-band gap of chlorine-based metal halide perovskites, good film-forming properties, and simple preparation. The gradient lithium conductive layer based on the metal halide perovskite realizes the isolation of the metal lithium anode and the electrolyte, and greatly improves the cycle stability of the lithium metal battery. The results were published in "Nature · Newsletter".

Metal halide perovskites have become hot materials in the field of optoelectronic research in recent years due to their advantages of adjustable band gap, high defect tolerance, and simple preparation. However, the metal halide perovskite material with a similar spatial structure as the lithium-ion conductor lithium lanthanum titanate has little research on the lithium ion conduction characteristics and related applications in the framework.

The researchers found that the metal chloride-based perovskite prepared by spin coating has the property of containing and transporting lithium ions. Lithium ions can be inserted into the crystal lattice of the metal halide perovskite, and can reversibly alloy / dealloy at the perovskite / substrate interface, forming a unique gradient structure of perovskite-alloy layer at the bottom . This unique gradient structure of perovskite-alloy layer is conducive to the uniform deposition / extraction of lithium ions on the electrode.

In addition, the researchers developed a convenient solid-phase transfer method to transfer the high-quality chloro-based perovskite thin film prepared by spin coating to the surface of the lithium foil in situ to form a lithium conductive layer with a gradient structure to achieve a dense The deposition and extraction of lithium metal avoids the growth of lithium dendrites and the pulverization of lithium metal electrodes. The final electrochemical cycle test shows that even under the strict conditions of lithium depletion and limited electrolyte, the capacity remains above 80% after 100 cycles, and the capacity of a lithium metal battery without a protective layer has been reduced to the initial level after 50 cycles 40%.

This achievement is the first attempt to apply the metal halide perovskite material to the lithium conductive layer at the interface of the lithium metal anode, and will provide more feasible ideas for the design of new solid electrolytes and the construction of high-performance lithium metal batteries. (Reporter Wu Changfeng)