MOF-derived NiZnCo-P nano-array for asymmetric supercapacitor
Xin Li, Jun Wang, Yan Yan, Pengwei Huo, Xinkun Wang
Abstract
The exposure of active sites on electrode materials is of utmost importance on the charging/discharging efficiency and capacitance of supercapacitors (SCs) electrode. However, regulating the surface of transition metal phosphide (TMP) electrodes to achieve highly exposed active sites remains a great challenge. In this work, we report a porous 2D-3D NiZnCo-P electrode with hierarchical structure on the carbon cloth (CC) with highly exposed active sites for high- capacitance SCs. Such a 2D-3D structure was derived from 3D porous ZnCo-MOF/CC and consequent 2D NiZnCo-LDH/CC template, which increases the interfacial contact with electrolyte ions and facilitates the charge transportation and ion diffusion of electrolyte among surface (diffusion coefficient = 3.5 × 10-9 cm2 s−1). As an anode for SCs, the champion 2D-3D NiZnCo-P/CC electrode exhibited the capacitance of 2816F g−1 at 1 A g−1, which is 1.27 times of the directly synthesized phosphide without 2D-3D structure and the highest capacitance for TMP electrodes reported so far. Moreover, the assembled 2D-3D NiZnCo-P//Zn-modified carbon nano-sheets ([email protected]) device demonstrate superior performance in terms of energy density (62.5 Wh kg−1) and durability (89.5% capacitance retention over 10,000 cycles).