Ni-Ce bimetal doping and phosphating modulated MOF with improved catalysis and adsorption for high-performance lithium-sulfur battery applications

Lithium-sulfur batteries (LSBs) have received widespread attentions because of high specific capacity and low cost. However, the low sulfur utilization and shuttle effect limited their wide application. In this paper, phosphating Ni-Ce bimetallic nanoparticles embedded in multifunctional freestanding porous carbon with improved catalytic activity and confinement were prepared from MOF materials. Compared with monoatomic catalysts or other homonuclear diatomic mixtures, the catalytic-adsorptive synergistic effect of Ni-Ce doping in NiCe@CPS can provide more active sites to catalyze the conversion of lithium polysulfides (LiPSs) to improve the reaction kinetics effectively, meanwhile, the phosphides Ni2P and CeP can physically and chemically adsorb the LiPSs to further inhibit the shuttle effect. Moreover, the porous carbon structure not only provides abundant channels for Li+ transport and electrolyte permeation but greatly facilitates sulfur storage and mitigates the volume expansion during the cycling process. The battery assembled with NiCe@CPS cathode delivered a discharge-specific capacity of 1013 mAh g−1 at 0.1 C, and maintained 768 mAh g−1 after 100 cycles with a Coulombic efficiency of 95 %.