Boron doped graphene cathode for capacitor via a new one-step method

Abstract

The graphene cathode was doped with boron via a new and fast method of plasma enhanced chemical vapor deposition (PECVD) at room temperature. Various plasma species of BHx (x = 0–3) with high reactivity reacted with graphene electrode via surface re-reactions and gas-interface intersection. The cathode made of boron doping into graphene (BG) exhibited excellent electrochemical performances in Li-ion capacitors, including a large discharge capacity of 140 mAh g−1 (voltage range: 1.5–4.2 V vs. Li/Li+, current density: 100 mA g−1) and the coulombic efficiency of more than 99.6% within 1000 circles. The capacity, coulombic efficiency and circle performance of the BG electrode were more superior to the undoped graphene electrode owing to the uniform doping of boron plasma species. The PECVD method has the advantages of being simple, is conducted at room-temperature, is time efficient and uniform, thus making it a fast and effective way for doping hetero-atoms into the electrode.