Interconnected MnO2 nanoflakes assembled on graphene foam as a binder-free and long-cycle life lithium battery anode

Abstract

Manganese dioxide (MnO2) is a promising anode material because of its high theoretical capacity, environmental friendliness and abundant natural reserves. However, its application in lithium ion batteries is still hindered by rapid capacity fading and low rate performance resulting from large volume expansion and low conductivity. We construct a stable structure with ultrathin interconnected MnO2 nanoflakes (NFs) assembled on the chemical vapor deposition (CVD) grown graphene foam (GF) via a facile hydrothermal process. Without the use of any binder, conductive additives or any other current collector, the designed electrode benefits from shorter transport path, larger electrode/electrolyte contact area, more stable structure to buffer volume expansion during cycling. As a result, the composites show increased cycle life and deliver a high capacity of about 1200mAhg−1 at the current density of 500mAg−1 after 300 cycles and a capacity higher than 500mAhg−1 at a current density of 5Ag−1.