Comparative study on electrochemical charge storage behavior of FeCo2S4 electrodes with different dimensional nanostructures

Abstract

The deep understanding of the electrochemical behavior of active materials is essential for the design of high-performance electrochemical energy storage devices. Herein, nanostructured FeCo2S4 electrodes with different dimensional morphologies [i.e., one dimensional nanoneedles (1D FeCo2S4), two dimensional nanosheets (2D FeCo2S4), and three dimensional structures consisting of nanosheets grafting on nanoneedles (3D FeCo2S4)] were in situ grown on carbon cloth via a robust hydrothermal strategy. Subsequently, the electrochemical charge storage behavior of such three FeCo2S4 electrodes was carefully investigated and analyzed through several electrochemical methods. It was revealed that the 3D FeCo2S4 electrode exhibited a considerable higher specific capacity (92.88 mAh g−1) as compared with 1D (58.42 mAh g−1) and 2D (26.00 mAh g−1) electrodes at a current density of 1 A g−1, which was mainly due to the superior charge transport characteristic from the rational combination between 1D and 2D units. Additionally, the 3D FeCo2S4 electrode indicated great stability in the cycling tests (∼82% capacity retention after 11200 cycles at 5 A g−1). Moreover, the quantitative calculation of the capacitive and diffusion-controlled contribution of three electrodes was performed to deep distinguish their electrochemical behavior based on different architectures. Thus, the design of 3D nanostructured electrodes will be an effective strategy to exploit high-performance electrochemical energy storage devices.