Sulfur and nitrogen in-situ co-doped hierarchical spherical porous carbon for efficient lithium storage

A new strategy is presented to fabricate sulfur and nitrogen in-situ co-doped hierarchical spherical porous carbon (SNHSPC) and porous carbon nanotube (PCNT) from conjugated microporous polymer using alkynyl monomers and dibromine aromatic compounds as the building blocks through Sonogashira–Hagihara cross-coupling reactions for efficient lithium storage. SEM, XRD, TEM, XPS, nitrogen adsorption/desorption analysis and Raman spectrum were used to determine the structure of SNHSPC and PCNT. SNHSPC is hierarchical spherical porous carbon particles constituted by aggregated porous nano-fibers, which is distinctly different from those of PCNT. SNHSPC feature hierarchical spherical porous carbon, high specific surface area and homogeneous S and N co-doping, which enable a superior lithium storage behavior. The synergy of hierarchically porous structure and dual heteroatoms make SNHSPC afford a high lithium storage capacity, outstanding cycling stability and large rate performance, which are all superior to those of PCNT. The initial reversible capacity of SNHSPC is as high as 776 mA h g−1 at 0.1 A g−1. •SNHSPC was fabricated from hierarchical spherical conjugated microporous polymer.•The obtained SNHSPC exhibits superior lithium storage behavior.•SNHSPC shows an initial reversible capacity of 776 mA h g−1 at 0.1 A g−1.•SNHSPC delivers 729 mA h g−1 at 0.2 A g−1 after 200 cycles.