Facile Preparation of High‐Content N‐Doped CNT Microspheres for High‐Performance Lithium Storage

Herein, high‐content N‐doped carbon nanotube (CNT) microspheres (HNCMs) are successfully synthesized through simple spray drying and one‐step pyrolysis. HNCM possesses a hierarchically porous architecture and high‐content N‐doping. In particular, HNCM800 (HNCM pyrolyzed at 800 °C) shows high nitrogen content of 12.43 at%. The porous structure derived from well‐interconnected CNTs not only offers a highly conductive network and blocks diffusion of soluble lithium polysulfides (LiPSs) in physical adsorption, but also allows sufficient sulfur infiltration. The incorporation of N‐rich CNTs provides strong chemical immobilization for LiPSs. As a sulfur host for lithium–sulfur batteries, good rate capability and high cycling stability is achieved for HNCM/S cathodes. Particularly, the HNCM800/S cathode delivers a high capacity of 804 mA h g−1 at 0.5 C after 1000 cycles corresponding to low fading rate (FR) of only 0.011% per cycle. Remarkably, the cathode with high sulfur loading of 6 mg cm−2 still maintains high cyclic stability (capacity of 555 mA h g−1 after 1000 cycles, FR 0.038%). Additionally, CNT/Co3O4 microspheres are obtained by the oxidation of CNTs/Co in the air. The as‐prepared CNT/Co3O4 microspheres are employed as an anode for lithium‐ion batteries and present excellent cycling performance. High‐content N‐doped carbon nanotube (CNT) microspheres (HNCMs) can be synthesized by simple spray drying and one‐step pyrolysis. HNCM possesses a hierarchically porous architecture and high‐content N‐doping. The porous structure originating from well‐interconnected N‐CNTs provides a highly conductive network. High‐content N‐doping offers strong chemical immobilization for polysulfides. These merits make HNCM an ideal host material for high‐performance Li–S battery.