Porous three-dimensional activated microwave exfoliated graphite oxide as an anode material for lithium ion batteries

Abstract

A porous graphene nanosheet, with a Brunauer–Emmett–Teller surface area of up to ∼3100 m² g⁻¹, is prepared by using chemical activation of microwave exfoliated graphite oxide. The sp²-bonded carbon has a continuous three-dimensional network of highly curved atom-thick walls with ∼1 to 5 nm width pores. As an anode material for lithium ion batteries, it can deliver a reversible specific capacity of ~1600 mA h g⁻¹ at the current of 100 mA g⁻¹. To understand the Li storage mechanism, porous carbon samples with tunable specific surface area were investigated. The high reversible capacity indicates that the meso- and micropores are the key factor for Li insertion/extraction during discharging and charging. The porous structure and large specific surface area is believed to have contributed to the high performance.