Covalent organic frameworks converted N, B co-doped carbon spheres with excellent lithium ion storage performance at high current density.

Covalent organic frameworks (COFs) with devisable nanostructures have exhibited extensive application prospects in energy storage and conversion. In this work, spherical COFs were successfully utilized as an ideal precursor for N, B co-doped carbon spheres (NBCs) that display hierarchical spherical architectures with rich pores. When applied as lithium ion batteries (LIBs) anode, NBCs exhibit high reversible specific capacity and outstanding long-life cycling stability (205.5 mAh g at 5.0 A g and 171.4 mAh g at 10.0 A g after 5000 cycles) owing to their hierarchical porosity, unique structure and in-situ N, B co-doping. The excellent lithium storage ability, especially satisfactory long cycling stability, enables NBCs to be a promising candidate for LIBs.