Nanostructured Li2MnSiO4/C Cathodes with Hierarchical Macro‐/Mesoporosity for Lithium‐Ion Batteries |
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Authors: | Guang He Arumugam Manthiram |
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Affiliation: | Materials Science and Engineering Program & Texas Materials Institute, The University of Texas at Austin, Austin, TX, USA |
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Abstract: | Li2MnSiO4/C nanocomposite with hierarchical macroporosity is prepared with poly(methyl methacrylate) (PMMA) colloidal crystals as a sacrificial hard‐template and water‐soluble phenol‐formaldehyde (PF) resin as the carbon source. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses confirm that the periodic macropores are ≈400 nm in diameter with 20–40 nm walls comprising Li2MnSiO4/C nanocrystals that produce additional large mesopores (< 30 nm) between the nanocrystals. The nanostructured Li2MnSiO4/C cathode exhibits a high reversible discharge capacity of 200 mAh g?1 at C/10 (16 mA g?1) rate at 1.5–4.8 V at 45 °C. Although the discharge capacity can be further increased on operating at 55 °C, the sample exhibits a relatively fast capacity fade at 55 °C, which can be partially solved by simply narrowing the voltage window to avoid side reactions of the electrolyte. The good performance of the Li2MnSiO4/C cathodes is attributed to the unique macro‐/mesostructure of the silicate coupled with uniform carbon coating. |
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Keywords: | lithium‐ion batteries polyanion cathodes Li2MnSiO4 hierarchical ordered macroporosity electrochemical performance |
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