Lithium
polysulfides (LiPSs) shuttling effect is the main problem
to be solved for cathode materials of lithium–sulfur batteries.
The adsorption and catalytic conversion of LiPSs by host materials
have become the main focus of cathode materials. In this work, transition
metal phosphides are combined with three-dimensional carbon nanosheets
to form an efficient and stable sulfur host material. The designed
composite material is effective in solving the problems of slow reaction
kinetics of Li–S batteries and LiPSs shuttling. Here, through
the supramolecular self-assembly process of melamine and phytic acid,
combined with soluble salt template technology, N- and P-codoped three-dimensional
hierarchical porous carbon materials with uniformly dispersed CoP
nanoparticles were efficiently synthesized. The catalytic effect of
CoP nanoparticles improves the reaction kinetics effectively of LiPS
conversion. The strong polarity of CoP nanoparticles is beneficial
to the adsorption of polysulfide ions. Moreover, the high specific
area provides more LiPS adsorption sites, and the doping of N and
P heteroatoms further increases the active sites of the composites.
The experimental results and theoretical calculations show that the
introduction of CoP promotes the conversion of LiPSs and accelerates
the nucleation rate of Li2S, thereby improving the electrochemical
performance of the composite as a sulfur host for lithium–sulfur
batteries.