In situ-formed cobalt nanoparticles embedded nitrogen-doped hierarchical porous carbon as sulfur host for high-performance Li-S batteries

Low redox kinetics and shuttle effect of polysulfides (PSs) is a grand challenge for practical applications of lithium-sulfur (Li-S) batteries. Herein, cobalt (Co) nanoparticles embedded inside nitrogen (N)-doped hierarchical porous carbon (MgCo-HC) are prepared via one-pot approach. As a result, MgCo-HC unique structure with the large surface area and Co, N-doping is proposed for the strong physical/chemical adsorption of PSs, high conductivity, fast redox reaction kinetics and the high S utilization. The resultant S cathode delivers a high specific capacity of 1086.4 mA h/g at 0.1 C, low-capacity fading rate of 0.041% per cycle over 880 cycles at 2 C, and superior rate performance up to 5 C. More intriguingly, the S/MgCo-HC electrode delivers reversible area capacities of 5.1 and 5.5 mA h/cm2 at 0.1 C under high S loading and learn electrolyte condition, respectively. Furthermore, the assembled Li-S soft-packaged battery is also readily assembled, which highlights stable electrochemical properties under folding conditions. This work provides a simple strategy to design advanced S hosts for the practical application of Li-S batteries with excellent electrochemical performance.