Graphene Sandwiched Mesostructured Li-Ion Battery Electrodes

A Li-ion battery electrode concept, consisting of an integrated 3D mesostructure of electrochemically active materials and graphene which provides a significantly greater active material loading than most other 3D structured electrode concepts. The combination of the 3D mesostructure, and the good electrical conductivity and low mass of grapheme enables realization of electrodes which exhibit high capacities, good cycle stability, and fast charge?discharge kinetics. In the V₂O₅ @graphene@ V₂O₅ cathode, an electrically conductive 4?10 layer thick graphene sheet was embedded between two 60 nm thick layers of electrochemically active V₂O₅.The structure was formed starting from a polystyrene (PS) opal templated electrodeposited Ni inverse opal. Graphene was grown on the opal via chemical vapor deposition (CVD). A first layer of V₂O₅ was then solvothermally grown onto the 3D graphene-coated Ni scaffold, followed by heat treatment. The Ni scaffold was etched, then another V₂O₅ layer was grown and thermally treated into the inner layer of graphene, forming a 3D sandwich nanoarchitecture electrode. The V₂O₅@graphene@ V₂O₅ cathode demonstration provides a full electrode basis capacity of about 230 mAh g^-1 at 5 C after 200 cycles, and =203 mAh g^-1 after 2000 cycles, with a Coulombic efficiency of =99.7%.