Doped Graphene Sheets As Anode Materials with Superhigh Rate and Large Capacity for Lithium Ion Batteries

TLDR

Lithium‑ion batteries must deliver both high power and large energy capacity at rapid charge/discharge rates, yet achieving this simultaneously remains a major challenge, and doped graphene’s two‑dimensional structure, defect‑rich surface, and enhanced conductivity are expected to facilitate fast Li⁺ uptake and electron transport. This study demonstrates that nitrogen‑ or boron‑doped graphene can serve as a high‑power, high‑energy anode material for lithium‑ion batteries under fast charge/discharge conditions. The doped graphene delivers a reversible capacity exceeding 1040 mAh g⁻¹ at 50 mA g⁻¹, can be charged and discharged within 1 h to several tens of seconds while maintaining high‑rate capability and long‑term cyclability, and achieves capacities of ~199 and 235 mAh g⁻¹ at 25 A g⁻¹ (≈30 s to full charge).

Abstract

One great challenge in the development of lithium ion batteries is to simultaneously achieve high power and large energy capacity at fast charge and discharge rates for several minutes to seconds. Here we show that nitrogen- or boron-doped graphene can be used as a promising anode for high-power and high-energy lithium ion batteries under high-rate charge and discharge conditions. The doped graphene shows a high reversible capacity of >1040 mAh g(-1) at a low rate of 50 mA g(-1). More importantly, it can be quickly charged and discharged in a very short time of 1 h to several tens of seconds together with high-rate capability and excellent long-term cyclability. For example, a very high capacity of ∼199 and 235 mAh g(-1) was obtained for the N-doped graphene and B-doped graphene at 25 A g(-1) (about 30 s to full charge). We believe that the unique two-dimensional structure, disordered surface morphology, heteroatomic defects, better electrode/electrolyte wettability, increased intersheet distance, improved electrical conductivity, and thermal stability of the doped graphene are beneficial to rapid surface Li(+) absorption and ultrafast Li(+) diffusion and electron transport, and thus make the doped materials superior to those of pristine chemically derived graphene and other carbonaceous materials.