Harnessing the Cutting-Edge Potential of 2d Mxene for Unleashing the Synergistic Advancement of Znse Microspheres in Asymmetric Pseudocapacitive Supercapacitor and H2 Production by Water Splitting

Abstract

In response to the increasing demand for sustainable energy, recent efforts have focused on developing novel composites with improved crystalline structures, chemical stability, and conductivity for electrochemical applications. Self-assembled zinc selenide (ZnSe) microspheres are synthesized by a simple hydrothermal process, and their electrochemical applications as a positive electrode/electrocatalyst in asymmetric pseudocapacitive supercapacitor (APSC) and water splitting are investigated. ZnSe is integrated into the two-dimensional (2D) Ti3C2Tx/MXene nanosheets that serve as a physical barrier to mitigate agglomeration, prevent side reactions of Zn, provide ZnSe with more sites and a steady Zn+2 supply, ultimately enhancing the electrochemical performance. Composite electrode demonstrates superior specific capacitance of 1,673.8 Fg⁻¹ at 1 Ag⁻¹, remarkable cyclic stability (98.81% capacity retention over 10,000 cycles), and excellent pseudocapacitive performance of 88% at 60 mVs-1. Density functional theory (DFT) simulations displayed highest adsorption energy for ZnSe@Ti3C2Tx/MXene, showcasing stable structure and strong electron interaction.  To demonstrate the commercial viability, active carbon (AC) is employed as the cathode to fabricate the AC//ZnSe@Ti3C2Tx-APSC device. In the water splitting assessment, ZnSe@Ti3C2Tx shows the lowest Tafel slopes (38 mVdec-1 for oxygen evolution reaction (OER) and 59.1 mVdec-1 for hydrogen evolution reaction (HER)). This novel approach significantly advances the overall performance of APSC and water-splitting.

Keywords: Electrochemical properties, Pseudocapacitive Supercapacitor, Ti3C2Tx/MXene, Composite Electrode, Density-Function Theory (DFT), Water splitting