Xinrui He,Yalin Hu,Hanqing Tian,Zhipeng Li,Pei Huang,Jing Jiang,Chao Wang
For pursing high-performance supercapacitors, both of the design strategy and structural characteristic of electrode materials are crucial. Herein, we report the in-situ growth of flexible self-assembled 3D hollow tubular Cu 2 S nanorods on Cu foam substrate (Cu 2 S@Cu). The Cu substrate is simultaneously acted as a copper source and a collector, which reduces the contact resistance. Moreover, the highly ordered 3D unique structure increases the redox reactive sites and enhances the ion transmission effectively, resulting in greatly improved electrochemical performance. Based on the Cu 2 S@Cu electrode, the supercapacitor exhibits high areal capacitance of 1000 mF cm −2 at a current density of 2 mA cm −2 , and great cycle stability, maintaining 96.9% capacitance after 10,000 cycles. Furthermore, the supercapacitor also shows an excellent flexibility with no significant decrease in the twisting or bending state. The capacity retention rates are 99.8% and 86.1%, respectively, and finally recover to 99.3%, confirming its great potential in practical application for portable electronic devices.
Water oxidation reaction often impedes the overall water splitting for the multi-step electron transfer process. Transition metal sulfides are earth abundant and widely studied for accelerating water splitting reactions. Cuprous sulfide, which is a common mineral and generally regarded as less active for oxygen evolution reaction, can also effectively promote water oxidation by introducing coarse surfaces on the as-prepared Cu 2 S nanorod arrays, with a largely increased double layer capacitance and thereby a greatly improved electrochemically active surface area, which only needs an overpotential of 360 mV to deliver 50 mA cm −2 and exhibits a rapid kinetics for oxygen evolution reaction. The fabrication strategy of creating coarse surfaces on pre-synthesized nanostructures for increased electrochemically active surface area can be promising for developing precious-metal-free electrocatalysts by providing more active sites and surface areas for water oxidation, and is also valuable for promoting the activity of less active but earth-abundant materials to achieve a better cost-effectiveness in scale-up application of water splitting technology.
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