Insights into the sandwich-like ultrathin Ni-doped MoS₂/rGO hybrid as effective sulfur hosts with excellent adsorption and electrocatalysis effects for lithium-sulfur batteries

The design of sulfur hosts with high conductivity, large specific surface area, strong adsorption and electrocatalytic ability is crucial to advance high performance lithium-sulfur batteries. Herein, a novel ultrathin sandwich-type Ni-doped MoS₂/reduced graphene oxide (denote as Ni-doped MoS₂/rGO) hybrid is developed as a sulfur host through a simple one-step hydrothermal route. The two-dimensional layered structure Ni-doped MoS₂/rGO hybrid with heterostructure and heteroatom architecture defects not only plays a key role in adsorption of lithium polysulfide but also catalyzes on redox kinetics of sulfur and polysulfide species. Meanwhile, it can contribute to the large specific surface area for Li₂S/S₈ deposition, fast Li-ion and electron transportation, thus enhancing the electrocatalytic properties, as confirmed firstly by cyclic voltammetry (CV) results. Due to the adsorption-catalytic synergistic effect, the Ni-doped MoS₂/rGO cathode exhibits high specific capacity (1343.6 mA h g⁻¹ at 0.2 C, 921.6 mA h g⁻¹ at 1 C), high coulombic efficiency and an outstanding cycle stability (with the low attenuation rate of 0.077% per cycle over 140 cycles at 0.5 C and 0.11% per cycle over 400 cycles at 1 C, respectively). This work proposes some inspiration for exploring the construction of advanced lithium-sulfur batteries through the rational design defects of atomic structure and electronic states of MoS₂ as sulfur host.