STRAIN INDUCED ENHANCED MIGRATION OF POLARON AND LITHIUM ION IN λ-MnO₂

Abstract

The dynamic properties of λ-MnO 2 under strain can be different to normal conditions as lithium storage material. Results from firstprinciples calculations show that compressive strain will enhance the electrical conductivity and lithium ion diffusion coefficient simultaneously. We show that 7% compressive strain applied along the (011) direction leads to about two orders of magnitude increase in both the electrical conductivity and Li diffusion coefficient under room temperature. 7% compressive strain applied along the (111) direction will increase the Li diffusion coefficient by five orders of magnitude. These results are important to experimental and industrial preparation and design of λ-MnO 2 materials when interfaces are involved. The physical mechanism behind the strain induced improvement of the dynamic performance is discussed.

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