Study of Fast Catalytic Conversion of Polysulfides by Porous N-Co₃O₄ Nanocages Embedded with rGONR/CNT Composite for High-Rate Li₂S-Based Lithium Sulfur Batteries

Lithium sulfide (Li2S)-based batteries are considered promising alternative sources for intercalation-type lithium-ion batteries because of their high theoretical capacity. However, the practical application of Li2S is limited by two major issues: the dissolution of polysulfides (PSs) and the poor electronic conductivity of the Li2S cathode materials. To tackle these problems, the as-prepared 3D porous cobalt oxide nanocages (N–Co3O4) were embedded with a two-dimensional (2D) graphene oxide nanoribbon (rGONR) and a one-dimensional (1D) carbon nanotube (CNT) carbon matrix to form N–Co3O4/rGONR/CNT (N–Co3O4/C) double-shelled metal–carbon composites. This study uses the infiltration–evaporation method to incorporate Li2S into the porous nanocage carbon structure (N–Co3O4/C) as a sulfur host material. This interconnected metal–carbon matrix design offered good electron conductivity (∼3.51 × 10–3 S cm–1), high diffusion coefficients, suitable surface area, and pore size (2 to 14 nm) for PS confinement. Our porous N–Co3O4 filler synergistically immobilized PSs inside the cathode via chemisorption, impeding the shuttle effect in LSBs. In situ XRD analysis reveals that the designed N–Co3O4/C with a spinel-based structure as a catalyst facilitates Li2S conversion with minimal polarization in the first cycle. The advantages of the as-fabricated Li2S–N–Co3O4/rGONR/CNT composite cathode delivered a high initial specific capacity of 1004 mA h g–1 at 0.1C and 413 mAh g–1 on the 1000th cycle at 3C, demonstrating good retention capability. Therefore, the N–Co3O4/C-modified composite cathode shows excellent electrochemical performance, implying that LSBs offer promising practical applications in high-performance energy storage devices.