Constructing a Flower-Like Microspherical Multifunctional Co3O4-NiO/mSiO2 Heterostructure toward Synergistic Regulation of Polysulfide with Ultrafast Charge Transfer Kinetics

The shuttle effect of lithium polysulfides (LiPSs) and their sluggish redox reaction kinetics severely impede the utilization efficiency of sulfur (S) and significantly deteriorate the cycling stability of lithium-sulfur (Li–S) batteries. Herein, a three-dimensional (3D) flower-like microspherical nanoarchitecture (Co3O4-NiO/mSiO2), in which the Co3O4-NiO heterojunction nanosheets are uniformly anchored onto mesoporous silica (mSiO2) nanospheres, is synthesized. This architecture is synthesized via a scalable hydrothermal approach. As a separator-modifying component, the mSiO2 nanospheres serve as structural templates, while the Co3O4-NiO heterointerfaces, rich in surface polar sites, provide dual functionality: (i) abundant chemical anchoring sites and intrinsically catalytic active sites for LiPSs, and (ii) a 3D mesoporous conductive network enabling efficient, coupled e–/Li+ transport. Owing to these advantages, the Li–S battery achieves an initial discharge capacity of 1017.6 mAh g–1 and retains 68% of that capacity after 1000 cycles at 2 C. Crucially, under realistic conditions of high S loading (5.1 mg cm–2) and lean electrolyte (E/S = 3.0 μL mg–1), the battery delivers a volumetric capacity of 804.1 Ah L–1 and an energy density of 1728.9 Wh L–1, retaining 864.5 Wh L–1 after 100 cycles. Furthermore, a prototype pouch battery delivered an initial discharge specific capacity of 986.3 mAh g–1 at 0.1 C with an elevated E/S ratio (5.5 μL mg–1). Collectively, this deep work demonstrate that rational engineering of a 3D heterostructured separator modifier constitutes a viable and scalable strategy toward practical high-energy-density Li–S batteries.