Sn-doped nickel sulfide (Ni3S2) derived from bimetallic MOF with ultra high capacitance

As a kind of high performance electrode material for supercapacitors, nickel sulfides has been widely used due to its facile synthesis, high activity, environmental friendliness, inexpensive price, and its performance can be greatly improved by reasonable structural design. Here, we have fabricated Sn-doped Ni3S2 (SNS) with a popcorn shaped morphology by a simple two-step hydrothermal reaction. In the first step, Ni-Sn MOF precursors were synthesized with terephthalic acid used as ligand. The precursors were then subjected to hydrothermal reaction with sodium sulfide as sulfur source to form SNS. As expected, the products exhibited excellent electrochemical performance due to the introduction of Sn, and among them, the specific capacitance of SNS was up to 1667 F g al at the current density of 1 A g(-1). Moreover, the asymmetric supercapacitor (ASC) device constructed by SNS and activated carbon (AC) has delivered a glorious cycle stability, and the capacitance still remained 83% of its original value even if it was charged and discharged continuously for 2000 times at high current density. Not only that, the maximum energy and power density were as high as 29.13 Wh kg(-1) and 0.7 kW kg(-1) respectively. All the excellent electrochemical performances indicated that SNS would have the potentiality to meet the ever-growing demand for energy storage. (C) 2020 Elsevier B.V. All rights reserved.