Facile in-situ growth of spore-like silica on layered MXene sheets for potential application in Supercapacitor

Intensive research on two-dimensional (2D) materials is going on through the past few decades, particularly in the area of supercapacitor applications exploiting their large surface area and high electrical conductivity. In recent years, MXene is a well-accepted layered electro-active 2D material, which has already proven its performance in energy storage. Despite being a novel electrode material, MXene suffers from restriction that includes its tendency to restack, causing a hindrance to the pathway for ion transport and resulting in low capacity and poor cycle life. In this endeavor, we have attempted to deal with the drawback of restacking of MXene sheets by the growth of silica network structure through a facile process of hydrothermal reaction. In our work, we have incorporated different concentrations of silica precursors into the MXene, and the electrochemical performance of all the studied composites have been examined to get a better insight into the contribution of silica to improve the specific capacitance value. The MXene/Silica composite exhibited a specific capacitance of 718 Fg⁻¹ in three electrode set up using 1 M H₂SO₄ electrolyte. Also a symmetric supercapacitor device was fabricated with the composite in 1 M H₂SO₄ with a specific capacitance of 648 Fg⁻¹ at a current density of 1 Ag⁻¹, approximately 3 times higher than pure MXene with a commendable rate capability of 80% and cycle stability of 97.8% at a current density of 20 Ag⁻¹ over 5000 cycles. This composite also exhibits an energy density of 130 WhKg⁻¹ at a power density of 1199 WKg⁻¹.