Nickel-embedded hierarchically-porous carbon microspheres as a multifunctional separator modifier for achieving advanced lithium-sulfur batteries

Lithium-sulfur batteries (LSBs), one of the most promising electrochemical energy storage systems, are in the spotlight due to their high theoretical energy density, alongside environmental friendliness and low cost of sulfur. Several unforgiving issues, however, hamper their commercial applications, such as the notorious shuttle effect of intermediary polysulfides and retarded redox kinetics, growth of dendritic Li, among other things. The crux of sorting out the problems above is designing a versatile material with good electrical conductivity, catalytic activity, together with abilities in suppression of polysulfide shuttling and Li dendrite growth. In this work, a composite of Ni nanoparticles embedded in the gradient-porous carbon micro-spheres (Ni/PCMS), acting like a miniature reactor, was fabricated as a separator modification material. Adequate electron conductivity can be guaranteed by the carbon substrate and the inlays of Ni nano-particles. The physical/chemical adsorption and high Li+ transference number of Ni/PCMS assure suppressed shuttle effect and Li dendrite growth, respectively. Catalytic activity is fulfilled with the exposed Ni active sites. As a consequence, the batteries based on Ni/PCMS-modified separators achieve a high initial discharge capacity of 1426.7 mAh g-1 at 0.1 C and a low capacity fading rate of 0.078% per cycle over 800 cycles at 1 C. Even under a high sulfur mass loading of & SIM; 3.0 mg cm-2, the battery still displays a superior rate perfor-mance of 555.6 mAh g-1 at 0.5 C. This work provides a thought for the rational design of a wide range of separator modifiers for high-performance Li-S batteries. & COPY; 2023 Elsevier B.V. All rights reserved.