MnO_(2)纳米线支撑中空十二面体CoNi_(2)S_(4)的制备及其电化学性能

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

采用简单的室温搅拌法和一步硫化法制备了MnO_(2)纳米线支撑中空十二面体CoNi_(2)S_(4)(MnO_(2)/CoNi_(2)S_(4))电极材料。超长MnO_(2)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CoNi_(2)S_(4)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,MnO_(2)/CoNi_(2)S_(4)在1 A·g^(-1)时具有1531.1 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MnO_(2)/CoNi_(2)S_(4)作为正极、活性炭(AC)为负极组装的MnO_(2)/CoNi_(2)S_(4)||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(5000次循环后保持64.8%)。

Using ultra⁃long MnO_(2)nanowires as templates and ZIF⁃67 as precursors,hollow bead string structured MnO_(2)/CoNi_(2)S_(4)was prepared via a simple room temperature stirring method and one⁃step vulcanization.In the unique structure,the ultra⁃long MnO_(2)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 hol⁃low and porous CoNi_(2)S_(4)provides richer active sites and mitigates the charging and discharging process of the vol⁃ume change during charging and discharging.Thanks to the above advantages,MnO_(2)/CoNi_(2)S_(4)had a specific capaci⁃tance value of 1531.1 F·g^(-1)at 1 A·g^(-1)and a capacitance retention rate of 86.9%at 10 A·g_(-1).Using MnO_(2)/CoNi_(2)S_(4)as the positive electrode and activated carbon(AC)as the negative electrode,the assembled MnO_(2)/CoNi_(2)S_(4)||AC devices achieved high energy density(40 Wh·kg^(-1)at 800 W·kg^(-1))and excellent cycling stability(64.8%retention after 5000 cycles).