Study of Fast Catalytic Conversion of Polysulfides by Porous N-Co<sub>3</sub>O<sub>4</sub> Nanocages Embedded with rGONR/CNT Composite for High-Rate Li<sub>2</sub>S-Based Lithium Sulfur Batteries
Gokul Raj Deivendran, Manojkumar Seenivasan, Yi–Shiuan Wu, Jeng‐Kuei Chang, Rajan Jose, Mrinal Poddar, Chia‐Liang Sun, Chun‐Chen Yang
Abstract
Lithium sulfide (Li 2 S)-based batteries are considered promising alternative sources for intercalation-type lithium-ion batteries because of their high theoretical capacity. However, the practical application of Li 2 S is limited by two major issues: the dissolution of polysulfides (PSs) and the poor electronic conductivity of the Li 2 S cathode materials. To tackle these problems, the as-prepared 3D porous cobalt oxide nanocages (N–Co 3 O 4 ) were embedded with a two-dimensional (2D) graphene oxide nanoribbon (rGONR) and a one-dimensional (1D) carbon nanotube (CNT) carbon matrix to form N–Co 3 O 4 /rGONR/CNT (N–Co 3 O 4 /C) double-shelled metal–carbon composites. This study uses the infiltration–evaporation method to incorporate Li 2 S into the porous nanocage carbon structure (N–Co 3 O 4 /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–Co 3 O 4 filler synergistically immobilized PSs inside the cathode via chemisorption, impeding the shuttle effect in LSBs. In situ XRD analysis reveals that the designed N–Co 3 O 4 /C with a spinel-based structure as a catalyst facilitates Li 2 S conversion with minimal polarization in the first cycle. The advantages of the as-fabricated Li 2 S–N–Co 3 O 4 /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–Co 3 O 4 /C-modified composite cathode shows excellent electrochemical performance, implying that LSBs offer promising practical applications in high-performance energy storage devices.