Despite great progress in lithium-sulfur batteries (LSBs), great obstacles still exist to achieve high loading content of sulfur and avoid the loss of active materials due to the dissolution of the intermediate polysulfide products in the electrolyte. Relationships between the intrinsic properties of nanostructured hosts and electrochemical performance of LSBs, especially, the chemical interaction effects on immobilizing polysulfides for LSB cathodes, are discussed in this Review. Moreover, the principle of rational microstructure design for LSB cathode materials with strong chemical interaction adsorbent effects on polysulfides, such as metallic compounds, metal particles, organic polymers, and heteroatom-doped carbon, is mainly described. According to the chemical immobilizing mechanism of polysulfide on LSB cathodes, three kinds of chemical immobilizing effects, including the strong chemical affinity between polar host and polar polysulfides, the chemical bonding effect between sulfur and the special function groups/atoms, and the catalytic effect on electrochemical reaction kinetics, are thoroughly reviewed. To improve the electrochemical performance and long cycling life-cycle stability of LSBs, possible solutions and strategies with respect to the rational design of the microstructure of LSB cathodes are comprehensively analyzed.

Employing phosphonium-based ionic liquid, tetrabutylphosphonium chloride [P 4444 ]Cl as novel phosphorus source and reaction medium, a facile approach for fabricating nanostructured Ni 2 P and Ni 12 P 5 was developed upon microwave heating in 1−2 min or conventional heating at 350 °C for 3 h. In a microwave-driven approach, controlling counteranions of various nickel salts could conveniently tune the phase of as-synthesized nickel phosphides. Ni(acac) 2 and Ni(OAc) 2 •4H 2 O as Ni source could yield Ni 2 P nanoparticles, while NiCl 2 •6H 2 O and NiSO 4 •7H 2 O offered Ni 12 P 5 nanocrystals. The synthesized products were characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. Their electrocatalytic behavior toward hydrogen evolution reaction in acidic medium was investigated. The assynthesized Ni 2 P nanoparticles presented more excellent catalytic efficiency than Ni 12 P 5 . Ni 2 P nanoparticles from Ni(acac) 2 require overpotentials of only 102 mV to reach 10 mA cm −2 with a small Tafel slope of 46 mV dec −1 , showing its best activity among those tested catalysts. The present novel ionic liquid-mediated strategy for the synthesis of nickel phosphide provides the remarkable advantage of operating in very short time by microwave heating, which is of particular interest from the viewpoint of energysaving, fast synthesis, and easy operation.

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