Crumpled nitrogen- and boron-dual-self-doped graphene sheets as an extraordinary active anode material for lithium ion batteries†
A novel three-dimensional, interconnected conducting layer network, comprised of crumpled nitrogen- and boron-dual-self-doped graphene sheets (NBGs) with an ultrahigh content of 7.72 at% nitrogen and 7.18 at% boron, has been synthesized through one-step thermolysis, using a borane-tert-butylamine complex as a precursor. The unique self-assembled 3D network structure offers shortened tunnels for lithium ion and electron transport and conduces the adsorption/desorption of lithium ions. As an anode material, NBGs-1000 reveals a high reversible capacity of up to 909 mA h g−1 and an excellent discharge capacity of 877 mA h g−1 after 125 cycles. It also exhibits a remarkable rate performance, including large capacities of 429 mA h g−1 and 318 mA h g−1 at 1 A g−1 and 2 A g−1, respectively. In contrast, a commercial graphite electrode has a capacity of less than 50 mA h g−1 at 1 A g−1. This demonstrates that crumpled NBGs are an extraordinary active anode material exhibiting a high capacity and good stability for lithium ion batteries, owing to their large surface area, heteroatomic defects, and the unique crumpled structure.