Bimetallic Co-Fe sulfide and phosphide as efficient electrode materials for overall water splitting and supercapacitor

Shiva Bhardwaj; Rishabh Srivastava; Teddy Mageto; Mahesh Chaudhari; Anuj Kumar; Jolaikha Sultana; Sanjay R Mishra; Felio Perez; Ram K Gupta

doi:10.1186/s11671-023-03837-1

Bimetallic Co-Fe sulfide and phosphide as efficient electrode materials for overall water splitting and supercapacitor

Discov Nano. 2023 Apr 4;18(1):59. doi: 10.1186/s11671-023-03837-1.

Authors

Shiva Bhardwaj^{1

2}, Rishabh Srivastava^{1

2}, Teddy Mageto^{1

2}, Mahesh Chaudhari^{2

3}, Anuj Kumar⁴, Jolaikha Sultana⁵, Sanjay R Mishra⁵, Felio Perez⁶, Ram K Gupta^{7

8}

Affiliations

¹ Department of Physics, Pittsburg State University, Pittsburg, KS, 66762, USA.
² National Institute of Material Advancement, Pittsburg State University, Pittsburg, KS, 66762, USA.
³ Department of Chemistry, Pittsburg State University, Pittsburg, KS, 66762, USA.
⁴ Nano-Technology Research Laboratory, Department of Chemistry, GLA University, Mathura, Uttar Pradesh, 281406, India. anuj.kumar@gla.ac.in.
⁵ Department of Physics and Materials Science, The University of Memphis, Memphis, TN, 38152, USA.
⁶ Integrated Microscopy Center, The University of Memphis, Memphis, TN, 38152, USA.
⁷ National Institute of Material Advancement, Pittsburg State University, Pittsburg, KS, 66762, USA. ramguptsmasu@gmail.com.
⁸ Department of Chemistry, Pittsburg State University, Pittsburg, KS, 66762, USA. ramguptsmasu@gmail.com.

Abstract

The major center of attraction in renewable energy technology is the designing of an efficient material for both electrocatalytic and supercapacitor (SC) applications. Herein, we report the simple hydrothermal method to synthesize cobalt-iron-based nanocomposites followed by sulfurization and phosphorization. The crystallinity of nanocomposites has been confirmed using X-ray diffraction, where crystalline nature improves from as-prepared to sulfurized to phosphorized. The as-synthesized CoFe-nanocomposite requires 263 mV overpotential for oxygen evolution reaction (OER) to reach a current density of 10 mA/cm² whereas the phosphorized requires 240 mV to reach 10 mA/cm². The hydrogen evolution reaction (HER) for CoFe-nanocomposite exhibits 208 mV overpotential at 10 mA/cm². Moreover, the results improved after phosphorization showing 186 mV to reach 10 mA/cm². The specific capacitance (C_sp) of as-synthesized nanocomposite is 120 F/g at 1 A/g, along with a power density of 3752 W/kg and a maximum energy density of 4.3 Wh/kg. Furthermore, the phosphorized nanocomposite shows the best performance by exhibiting 252 F/g at 1 A/g and the highest power and energy density of 4.2 kW/kg and 10.1 Wh/kg. This shows that the results get improved more than twice. The 97% capacitance retention after 5000 cycles shows cyclic stability of phosphorized CoFe. Our research thus offers cost-effective and highly efficient material for energy production and storage applications.

Keywords: Cobalt-iron; Electrocatalysts; Nanocomposites; Phosphorized; Sulfide; Supercapacitor.