▎ 摘　　要

Rational design of carbon materials for electrochemical devices has attracted great attentions over the past decades. Doping carbon with heteroatoms has been widely proven to be an effective way to improve the physical and electrochemical properties of carbon. The selective types and doping level of heteroatoms, as well as simple and green doping routes, are keys to the development of heteroatoms doped carbon. Due to a strong synergistic effect generated by the co-doping of boron (B) and nitrogen (N), B, N co-doped carbon materials have been demonstrated to be promising catalysts for multiple electrochemical devices. Herein, we report an eco-friendly and one-step approach to synthesis of B, N co-doped graphene (B, N-G) using BN as B and N doping resources. The decomposition of BN under a controlled flow of water steam at high temperature not only enables a high-level B and N co-doping into carbon but also facilitates the formation of highly active catalytic sites. Benefiting from high co-doping level of heteroatoms and highly active catalytic sites (e.g., BC2O), the B, N-G as cathode for rechargeable lithium oxygen batteries displays outstanding lithium storage properties with an ultrahigh specific capacity of 18222 mAh g(-1) at 100 mA g(-1) and good cycling stability with a limited specific capacity of 1000 mAh g(-1) over 120 cycles at 1 A g(-1).