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 hol-low and porous CoNi2S4 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,MnO2/CoNi2S4 had a specific capaci-tance 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).
metal-organic frameworkmanganese dioxide nanowiretransition metal sulfidesupercapacitor
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