Electrochemical intercalation of Mg2+ in 3D hierarchically porous magnesium cobalt silicate and its application as an advanced cathode material in rechargeable magnesium batteries

Abstract

We firstly report the formation of 3D hierarchically porous MgCoSiO₄ and the electrochemical intercalation of the bivalent cation Mg²⁺ in MgCoSiO₄ with regard to its use as a cathode material in rechargeable magnesium batteries. Reversible Mg²⁺ intercalation can be demonstrated and the process is enhanced by the use of a novel 3D hierarchically porous architecture, consisting of a network of macropores with several nanometre wall and mesopores at the boundaries of grains or between grains. It is suggested that the interconnected wall structure, dual porosity and high surface area reduces the solid-state diffusion lengths for Mg diffusion, facilitates electrolyte penetration into particles and provides a large number of active sites for charge-transfer reactions.