Abstract
Rational design of hybrid carbon host with high electrical conductivity and strong adsorption toward soluble lithium polysulfides is the main challenge for achieving high-performance lithium-sulfur batteries (LSBs). Herein, novel binder-free Ni@N-doped carbon nanospheres (N-CNSs) films as sulfur host are firstly synthesized via a facile combined hydrothermal-atomic layer deposition method. The cross-linked multilayer N-CNSs films can effectively enhance the electrical conductivity of electrode and provide physical blocking "dams" toward the soluble long-chain polysulfides. Moreover, the doped N heteroatoms and superficial NiO layer on Ni layer can work synergistically to suppress the shuttle of lithium polysulfides by effective chemical interaction/adsorption. In virtue of the unique composite architecture and reinforced dual physical and chemical adsorption to the soluble polysulfides, the obtained Ni@N-CNSs/S electrode is demonstrated with enhanced rate performance (816 mAh g-1 at 2 C) and excellent long cycling life (87% after 200 cycles at 0.1 C), much better than N-CNSs/S electrode and other carbon/S counterparts. Our proposed design strategy offers a promising prospect for construction of advanced sulfur cathodes for applications in LSBs and other energy storage systems.