Custom designed nanocrystalline Li2MSiO4/reduced graphene oxide (M = Fe, Mn) formulations as high capacity cathodes for rechargeable lithium batteries

Abstract

Nanocrystalline Li₂MSiO₄ (M = Fe, Mn) particles embedded between in situ formed rGO sheets are obtained by adopting customized solvothermal synthesis. An appreciable room temperature specific capacity of 149 mA h g⁻¹ with 89% capacity retention and 210 mA h g⁻¹ with 87% retention have been exhibited by Li₂FeSiO₄/rGO and Li₂MnSiO₄/rGO composites, corresponding to the participation of close to one and more than one lithium per formula unit respectively. The formation of nanocrystalline Li₂MSiO₄ (M = Fe, Mn) compounds in the desired phase and the complete wrapping of orthosilicates with rGO sheets are believed to be responsible for the excellent electrochemical behavior of the orthosilicate cathodes of the present study to best suit with requirements of rechargeable lithium-ion batteries. The abundant availability and eco-benignity advantages of Fe and Mn are valuable additions in the consideration of Li₂MSiO₄/rGO (M = Fe, Mn) cathodes as sustainable potential candidates.