Sea urchin-like CoNi2S4 materials derived from nickel hexamyanocobaltate for high-performance asymmetric hybrid supercapacitor

Abstract

In this work, a mild chemical precipitation method and simple hydrothermal treatment of the nickel hexamyanocobaltate precursor strategy are developed to prepare a sea urchin-like CoNi2S4 compound with remarkable specific capacity and excellent cycling stability. The prepared CoNi2S4 has an outstanding specific capacity of 149.1 mA h g−1 at 1 A g−1 and an initial capacity of 83.1% after 3000 cycles at 10 A g−1. Moreover, the porous carbon nanospheres (PCNs) with exhibit cycling stability (94.7% of initial specific capacity after 10 000 cycles at 10 A g−1) are selected as negative electrode to match CoNi2S4 positive electrode for assembly of CoNi2S4//PCNs asymmetric supercapacitor (ASC). Satisfactorily, the as-assembled CoNi2S4//PCNs ASC exhibits an impressive energy density of 41.6 Wh kg−1 at 797 W kg−1, as well as the suitable capacity retention of 82.8% after 10 000 cycles. The superior properties of the device demonstrated that the as-prepared material is potential energy storage material.