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

摘要

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 1200 mAh g(-1)at the current density of 500 mA g(-1). after 300 cycles and a capacity higher than 500 mAh g(-1) at a current density of 5 A g(-1). (C) 2015 Elsevier Ltd. All rights reserved.