Sha Wanli, Huang Xin, Zhang Jun, Luo Yang, Du Jianhui, Wang Jianxin, Pan Hong, Liu Ning
College of Materials Science and Engineering, Qiqihar University, Qiqihar, Heilongjiang Province 161006, China.
College of Materials Science and Engineering, Qiqihar University, Qiqihar, Heilongjiang Province 161006, China.
J Colloid Interface Sci. 2025 Sep 15;694:137681. doi: 10.1016/j.jcis.2025.137681. Epub 2025 Apr 23.
The "shuttle effect" and slow reaction kinetics caused by the diffusive polysulfides (LiPSs) in lithium-sulfur batteries have seriously hindered the superiorities of high theoretical capacity and energy density of sulfur cathode. Metal compounds serve as cathode carrier materials for lithium-sulfur batteries can adsorb LiPSs and accelerate the sulfur redox reaction. Compared with monometallic systems, bimetallic components usually expose richer active sites, which facilitates the kinetics of LiPSs during the redox process. However, due to the limitation of morphology and structure, the catalytic capacity of single metal atom and the synergistic effect between bimetal atom are still not fully utilized, leading to the still poor reaction kinetics. Especially, their application effect in thick electrode with high sulfur load is significantly reduced. In this study, chemical etching reaction was utilized to convert zeolitic imidazolate framework (ZIF) 67 into a polyhedral hierarchical structured material stacked with layered double hydroxide (NiCo-LDH) nanosheets, and based on this, it was transformed into nickel cobalt sulfoselenide (NiCoSSe) with quaternary hierarchical structure. The bimetallic sulfoselenide obtained by this strategy retain the high specific surface area of the ZIF structure, thus providing more active sites for adsorption of LiPSs and catalyzing sulfur redox. Importantly, it was demonstrated by density-functional theory (DFT) calculations that, selenium doping can further enhance the interaction between Ni and Co atoms in NiCoSSe, which promotes the conversion of LiPSs and significantly improves the redox kinetics of the battery. An initial specific capacity of up to 1093.4 mAh g at a current density of 0.1C as well as a capacity retention of 98.2 % after 500 charge-discharge cycles at a current density of 2C were obtained based on the cathode with NiCoSSe carrier. By systematically investigating the synthesis of bimetallic sulfoselenide compounds and their enhancement effects on the reaction kinetics of lithium-sulfur battery cathode, this study will provide a detailed reference for the conformational relationship between the structure of quaternary NiCoSSe materials and electrochemical performance.
锂硫电池中扩散性多硫化物（LiPSs）引起的“穿梭效应”和缓慢的反应动力学严重阻碍了硫正极高理论容量和能量密度的优势。用作锂硫电池阴极载体材料的金属化合物可以吸附LiPSs并加速硫氧化还原反应。与单金属体系相比，双金属组分通常暴露更丰富的活性位点，这有利于LiPSs在氧化还原过程中的动力学。然而，由于形态和结构的限制，单金属原子的催化能力和双金属原子之间的协同效应仍未得到充分利用，导致反应动力学仍然较差。特别是，它们在高硫负载厚电极中的应用效果显著降低。在本研究中，利用化学蚀刻反应将沸石咪唑酯骨架（ZIF）67转化为层状双氢氧化物（NiCo-LDH）纳米片堆叠的多面体分级结构材料，并在此基础上转化为具有四级分级结构的镍钴硫硒化物（NiCoSSe）。通过该策略获得的双金属硫硒化物保留了ZIF结构的高比表面积，从而为LiPSs的吸附和催化硫氧化还原提供了更多活性位点。重要的是，密度泛函理论（DFT）计算表明，硒掺杂可以进一步增强NiCoSSe中Ni和Co原子之间的相互作用，促进LiPSs的转化并显著改善电池的氧化还原动力学。基于具有NiCoSSe载体的阴极，在0.1C电流密度下初始比容量高达1093.4 mAh g，在2C电流密度下500次充放电循环后容量保持率为98.2%。通过系统研究双金属硫硒化物化合物的合成及其对锂硫电池阴极反应动力学的增强作用，本研究将为四级NiCoSSe材料结构与电化学性能之间的构效关系提供详细参考。
