Free-standing reduced graphene oxide/MnO2-reduced graphene oxide-carbon nanotube nanocomposite flexible membrane as an anode for improving lithium-ion batteries.

To solve the barriers of poor rate capability and inferior cycling stability for the MnO2 anode in lithium ion batteries, we present a highly flexible membrane anode employing two-dimensional (2D) reduced graphene oxide sheets (rGO) and a three-dimensional (3D) MnO2-reduced graphene oxide-carbon nanotube nanocomposite (MGC) by a vacuum filtration and thermal annealing approach. All the components in the 2D/3D thin film anode have a synergistic effect on the improved performance. The initial discharge specific capacity of the electrode with the MnO2 content of 56 wt% was 1656.8 mA h g-1 and remains 1172.5 mA h g-1 after 100 cycles at a density of 100 mA g-1. On enhancing the density to 200 mA g-1, the membrane-electrode still exhibits a large reversible discharging capacity of ∼948.9 mA h g-1 after 300 cycles. Moreover, the flexible Li-ion battery with a large area also shows excellent electrochemical performance in different bending positions, which provides the potential for wearable energy storage devices.