context: Moreover, the formation of metal sulfides with a non-crystalline structure also reveals enhanced adsorption/bonding of LiPSs owing to abundant defects and dangling bonds. For example, amorphous TiS4 has been successfully prepared by Sakuda et al. through a mechanical milling process using crystalline TiS2, sulfur, and acetylene black. When used as the cathode in a Li–S battery, the dissolution of LiPSs into the electrolyte is significantly suppressed because amorphization reduces the symmetry of the lattice, leading to the possibility of overlapping electron clouds between sulfur and titanium atoms, resulting in chemical bonding between the elements. Liu et al. reported the synthesis of a S@amorphous NiS2 composite via a coprecipitation reaction using Na2S8 and NiCl2 ethanol solution. Here the soluble sulfide ions can permeate into the loose amorphous structure, and thus the S particle would nucleate and grow in the inner space of NiS2, ensuing the high immobilization of S species. Very recently, Yu et al. meticulously designed hollow-amorphous N-doped carbon/MoS3 nanoboxes (NC/MoS3 NBs) as an advanced sulfur host for Li–S batteries. In a typical synthesis, crystalline α-Fe2O3 nanocubes are first coated with a layer of polydopamine, which are then calcined in a N2 atmosphere and etched in HCl solution to obtain N-doped carbon (NC) shells and hollow NC nanoboxes, respectively. Finally, the NC/MoS3 NB host is prepared through heterogeneous nucleation using CTAB as the surfactant and (NH4)2MoS4 as the precursor. Here, the amorphous MoS3 with unsaturated coordination Mo and electron-rich S not only has strong binding capability to LiPSs but also exhibits a catalytic effect on polysulfide conversion, which are verified by both experimental investigations and theoretical calculations. More interestingly, this synthesis strategy can be generalized to fabricate other amorphous metal chalcogenides nanoboxes such as CoSx and WSx, which is also promising to be applied in the fields of energy storage and conversion.
answer: LiPSs 