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 approximate to 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 degrees C. Although the discharge capacity can be further increased on operating at 55 degrees C, the sample exhibits a relatively fast capacity fade at 55 degrees 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.