Enhanced performance of lithium-sulfurized polyacrylonitrile batteries via multifunctional CoS2/NiS2 heterostructures and intrinsic electric fields

초록

Lithium-sulfurized polyacrylonitrile (Li-SPAN) batteries are an advanced class of Li–S energy storage systems that effectively mitigate the polysulfide shuttle effect. However, conventional SPAN cathodes experience low active material retention (< 40 wt%) and sluggish electrochemical kinetics, which limit their practical application. To address these challenges, this study introduces a CoS2/NiS2@SeSPAN composite nanofiber membrane as a high-performance Li-SPAN cathode. The cathode was synthesized through electrospinning Co/Ni salts with PAN, followed by hydrothermal deposition of Ni-ZIF-67 and SeSx-assisted thermal treatment to form a CoS2/NiS2 heterostructure within the SeSPAN matrix. Experimental validation and density functional theory simulations confirmed that the cathode electrolyte interphase layer effectively encapsulated the active material, extending the solid-state reaction pathway. This hierarchical porous architecture enabled a high active material loading of 59 wt%, which considerably exceeds that of conventional SPAN-based cathodes. The three-dimensional interconnected fiber network maximized the exposure of the CoS2/NiS2 heterojunction, while the metal sulfides increased the conductivity to facilitate efficient electron and ion transport. The intrinsic electric field within the CoS2/NiS2 heterostructure further enhanced polysulfide adsorption and catalytic conversion, accelerating the electrochemical kinetics. As a result, the CoS2/NiS2@SeSPAN cathode had an initial discharge capacity of 678 mAh g−1 at 0.2C, maintaining 634 mAh g−1 at 0.5C. Remarkably, the battery maintained 98.2% of its capacity after 800 cycles, highlighting its outstanding long-term cycling stability. The substantial potential of CoS2/NiS2@SeSPAN for high-performance Li-SPAN batteries and the critical role of heterostructure engineering in next-generation energy storage technologies are highlighted in this study. © Youke Publishing Co., Ltd. 2025.

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