Ultrafine nanoparticles of tin-cobalt-sulfide decorated over 2D MXene sheets as a cathode material for high-performance asymmetric supercapacitor.

[Display omitted] • Newly designed and sustainable 0D/2D Sn-Co-S/MXene cathode material is reported for asymmetric supercapacitor. • 0D/2D Sn-Co-S/MXene hybrid material contributes a high specific capacity value of 305.71 mA h gm⁻¹ at 1 A g⁻¹. • The Sn-Co-S/MXene hybrid material has displayed phenomenal electrochemical performance owing to its highly electroactive and conductive architecture. • The Sn-Co-S/MXene//AC ASC device operated at 1.70 (V) displays a high energy density of 43.55 Wh Kg⁻¹. The design of electrode materials for improved electrochemical properties and stable geometric configuration is known as effective research in developing the electrochemical capability of supercapacitors (SCs). However, there is a difficulty in designing innovative composite material with excellent electrical conductivity and superior specific capacity by way of low cost and easy synthesis process. Herein, for the first time, a stable Sn-Co-S/MXene hybrid material is fabricated through the electrochemical assembly by combining positively charged ultrafine Sn-Co-S nanoparticles (NPs) and negatively charged 2D Ti 3 C 2 Tx (MXene) sheets due to electrostatic interaction. The Sn-Co-S/MXene hybrid material has displayed excellent electrochemical performance with an ultrahigh specific capacity of 305.71 mA h gm⁻¹ at 1 A g⁻¹ and capacity retention of 94.8% after 10, 000 charge–discharge cycles. The Sn-Co-S/MXene hybrid material of high electrochemical performance has improved charge transfer kinetics during the charge–discharge process, due to the synergistic coupling effect between ultrafine Sn-Co-S nanoparticles and MXene sheets. Furthermore, the Sn-Co-S/MXene//activated carbon (AC) asymmetric supercapacitor (ASC) device has been configured with the assistance of Sn-Co-S/MXene as cathode and AC as anode materials. The Sn-Co-S/MXene//AC ASC device exhibits a stable potential window of 1.7 V, a high specific capacitance of 108.50F g⁻¹ at 1 A g⁻¹, and an energy density of 43.55Wh kg⁻¹ at a power density of 0.83 kW kg⁻¹. This study validates the design and application of highly electroactive Sn-Co-S/MXene hybrid electrode material for ultrastable asymmetric supercapacitors. [ABSTRACT FROM AUTHOR]