摘要

Silicate cathode material Li2MSiO4 (M = Mn, Fe, Co) receives wide attention due to high theoretical capacity. However, the lack of electrochemical properties and cycle stability limit its further development. The effect of the mechanical properties of Li2MSiO4 (M = Mn, Fe, Co) system on its electrochemical properties is systematically studied by the first-principles calculations based on density functional theory within the generalized gradient approximation with Hubbard corrections (GGA+U). The calculation results suggest that the Li2MSiO4 (M = Mn, Fe, Co) show good toughness, especially Li2FeSiO4, which is consistent with the experimental report that Li2FeSiO4 has excellent cyclic stability. In addition, the study finds that Li2CoSiO4 has the highest Young's modulus E and Debye temperature θD, which is consistent with the experimental results of higher discharge voltage and Li+ difficult detachment from the Li2CoSiO4.

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