Modulating electron redistribution via atomic Cu incorporation in Mott-Schottky Ni/NiO heterostructures for superior...

The redox kinetics of lithium polysulfides (LiPSs) result from the intrinsic insulating nature of sulfur and the weak interaction between hosts and LiPSs. Constructing heterostructures with built-in electric fields is a promising strategy to accelerate charge transfer; however, the limited active sites and suboptimal electronic configuration at the interface often restrict their catalytic efficiency. Herein, we propose an atomic-level modulation strategy by incorporating isolated Cu atoms into a Mott-Schottky Ni/NiO heterostructure to create a multifunctional electrocatalytic layer for LiS batteries. The introduction of atomic Cu not only induces abundant oxygen vacancies but also triggers a selective upward shift of the d-band center, which synergizes with the interfacial electric field to optimize the electron redistribution. This electronic restructuring significantly enhances the orbital hybridization between the host and LiPSs, thereby strengthening the chemical adsorption and effectively lowering the decomposition energy barrier of Li₂S. Consequently, the Cu-Ni/NiO modified separator exhibits superior catalytic activity, achieving a high initial capacity of 1353 mAh g^-1 and an ultralow decay rate of 0.056% per cycle over 500 cycles at 1C. Even under harsh conditions with high sulfur loading (8.4 mg cm^-2) and lean electrolyte, the pouch cell delivers a high areal capacity of 4.16 mAh cm^-2 and excellent flexibility, demonstrating its great potential for practical applications.