MnO2纳米线支撑中空十二面体CoNi2S4的制备及其电化学性能

采用简单的室温搅拌法和一步硫化法制备了 MnO₂纳米线支撑中空十二面体 CoNi₂S₄ (MnO₂/CoNi₂S₄)电极材料。超长MnO₂纳米线为电子转移提供了直接路径,而且其较大的长径比有利于形成自支撑的三维导电网络结构;中空多孔的CoNi₂S₄提供了更丰富的活性位点,同时缓解了充放电过程中的体积变化。得益于以上优势,MnO₂/CoNi₂S₄在1 A·g^-1时具有1 531.1 F·g^-1的比电容,在 10 A·g^-1时具有 86.9% 的电容保持率。利用 MnO₂/CoNi₂S₄作为正极、活性炭(AC)为负极组装的 MnO₂/CoNi₂S₄||AC器件实现了高能量密度(800 W·kg^-1时40 Wh·kg^-1)和优异的循环稳定性(5 000次循环后保持64.8%)。

Preparation and electrochemical properties of hollow dodecahedral CoNi2S4 supported by MnO2 nanowires

Using ultra-long MnO₂ nanowires as templates and ZIF-67 as precursors, hollow bead string structured MnO₂/CoNi₂S₄ was prepared via a simple room temperature stirring method and one-step vulcanization. In the unique structure, the ultra-long MnO₂ nanowires provide a direct pathway for electron transfer, and their large aspect ratio is conducive to the formation of self-supporting three-dimensional conductive network structure; the hollow and porous CoNi₂S₄ provides richer active sites and mitigates the charging and discharging process of the volume change during charging and discharging. Thanks to the above advantages, MnO₂/CoNi₂S₄ had a specific capacitance value of 1 531.1 F·g^-1 at 1 A·g^-1 and a capacitance retention rate of 86.9% at 10 A·g^-1. Using MnO₂/CoNi₂S₄ as the positive electrode and activated carbon (AC) as the negative electrode, the assembled MnO₂/CoNi₂S₄||AC devices achieved high energy density (40 Wh·kg^-1 at 800 W·kg^-1) and excellent cycling stability (64.8% retention after 5 000 cycles).