Nitrogen doped graphite felt decorated with porous Ni1.4Co1.6S4 nanosheets for 3D pseudocapacitor electrodes

Abstract

3D electrodes are of significant importance for the development of wearable electronics. In this manuscript, nitrogen doped graphite felt (NGF) and Ni_1.4Co_1.6S₄ have been selected as a 3D conducting matrix and redox-active species for pseudocapacitor electrodes, respectively. The hydrothermal growth of Ni_1.4Co_1.6S₄ in the presence of NGF yields stand-alone and bendable composite electrodes where Ni_1.4Co_1.6S₄ forms porous nanosheets dispersed uniformly along the NGF surface. The experimental results show that the Ni_1.4Co_1.6S₄/NGF electrode achieves a remarkable specific capacitance of 1625 F g⁻¹ at a current density of 1 A g⁻¹, which is maintained at 1465 F g⁻¹ when the current density is increased to 20 A g⁻¹. After cycling at a current density of 20 A g⁻¹ for 2000 cycles, the Ni_1.4Co_1.6S₄/NGF electrode still delivers 90.2% of its original specific capacitance. Such encouraging rate capability and cycling stability of the Ni_1.4Co_1.6S₄/NGF electrode are attributed to the desirable Ni_1.4Co_1.6S₄ nanostructure and the synergistic effect of the good electron conductivity and excellent surface property of the NGF substrate. The outstanding electrochemical performance of the Ni_1.4Co_1.6S₄/NGF electrode makes it a promising candidate for 3D pseudocapacitor applications.