Ion diffusion efficiency at the solid-liquid interface is an important factor for energy storage and adsorption from aqueous solution. Although K2 Mn4 O8 (KMO) exhibits efficient ion diffusion and ion-exchange capacities, due to its high interlayer space of 0.70 nm, how to enhance its mass transfer performance is still an issue. Herein, novel layered KMO/reduced graphene oxide (RGO) nanocomposites are fabricated through the anchoring of KMO nanoplates on RGO with a mild solution process. The face-to-face structure facilitates fast transfer of lithium and lead ions; thus leading to excellent lithium storage and lead ion adsorption. The anchoring of KMO on RGO not only increases electrical conductivity of the layered nanocomposites, but also effectively prevents aggregation of KMO nanoplates. The KMO/RGO nanocomposite with an optimal RGO content exhibits a first cycle charge capacity of 739 mA h g-1 , which is much higher than that of KMO (326 mA h g-1 ). After 100 charge-discharge cycles, it still retains a charge capacity of 664 mA h g-1 . For the adsorption of lead ions, the KMO/RGO nanocomposite exhibits a capacity of 341 mg g-1 , which is higher than those of KMO (305 mg g-1 ) and RGO (63 mg g-1 ) alone.
Keywords: adsorption; electrochemistry; graphene; layered compounds; nanostructures.
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