Facile in situ nitrogen-doped carbon coated iron sulfide as green and efficient adsorbent for stable lithium–sulfur batteries

As the vital component affecting the performance of lithium-sulfur (Li-S) battery, the cathode host materials are of great importance. In order to pursue the high sulfiphility to obtain good performance, vast environmentally hazardous heavy metals were introduced, increasing the production costs and hindering Li-S battery real application to a certain extent. Along with performance, cost and environmental safety are keys but neglected point, for scalable fabrication of Li-S batteries host material. Here, an economical, efficient yet green adsorbent N-doped carbon-coated iron sulfide (abbreviated as FeS/N-C) has been synthesized via a simple pyrolysis approach. The achieved FeS/N-C exhibits rich element doping of nitrogen and uniform nanosheet morphology, self-assembling into stable nanoflower structures. As a sulfur host, the FeS/N-C not only avoids the introduction of the precarious heavy metals, reduces costs but also presents high sulfiphility to achieve extraordinary electrochemical performance. With a sulfur content of 70.8 wt%, the FeS/N-C based sulfur electrodes deliver a high reversible capacity of about 729 mA h/g at 0.5 C after 500 cycles, with the degradation of 0.013% per cycle. Even at a higher rate of 2.0 C, a reversible capacity of 438 mA h/g still remains after 1000cycles. This green and highly efficient host material provides cost-effective solution to large-scale commercial applications of Li-S battery.