Tessellated N-doped carbon/CoSe2 as trap-catalyst sulfur hosts for room-temperature sodium–sulfur batteries

Abstract

The construction of highly conductive structures with excellent adsorption–catalytic properties to accelerate electron transfer and suppress polysulfide shuttle is considered as an effective strategy to achieve well-performing sodium–sulfur batteries. Herein, a self-supported tessellated N-doped carbon/CoSe₂ (NCCS) is developed as a sulfur host for sodium–sulfur batteries by a simple deposition–selenization of lyophilized bacterial cellulose (BC), where NC acts as a conductive network to ensure the rapid initiation of efficient catalytic reactions at the tessellated CoSe₂ interface and maintain good structural stability. The CoSe₂ nanoparticles provide strong ability in anchoring, trapping and catalyzing polysulfides. As a result, the prepared tessellated NCCS@S cathode demonstrates a high initial discharge specific capacity of 871.3 mA h g⁻¹ at a current rate of 0.1C and good electrochemical stability for up to 500 cycles at 1C.