Tin(IV) selenide anchored-biowaste derived porous carbon-Ti3C2Tx (MXene) nanohybrid: An ionic electrolyte enhanced high performing flexible supercapacitor electrode

Abstract

A facile hydrothermal growth and intercalation of tin(IV) selenide (SnSe2) over the interface of activated porous carbon (APC)/Ti3C2Tx (MXene) were studied as a positive electrode for asymmetric flexible supercapacitor. The porous carbon was derived from the walnut shell biowaste and activated with KOH to obtain a highly porous uniform structure (APC), which gets encapsulated by Ti3C2Tx sheets and restricted the restacking tendency of Ti3C2Tx leading to the increment in electrochemical activity. Additionally, SnSe2 plays a crucial role by incorporating reactive centers over the APC/Ti3C2Tx binary composites, which greatly enhanced the electrode capacitance. Due to the excellent morphological feature, the best electrochemical performance was obtained from APC/Ti3C2Tx/SnSe2 with an outstanding specific capacitance of 815 F g-1 in a three-electrode setup. Device performances of APC/Ti3C2Tx/SnSe2 as cathode were tested using both organic and ionic [(NEt3H)+(HSO4)-] electrolytes. However, the supercapacitor device revealed superior supercapacitive performances in ionic electrolyte having an outstanding energy density (102 Wh kg- 1), specific capacitance (227 F g-1), and decent rate capability. The estimated volumetric energy density in the ionic electrolyte for the device was 1.887 mW h cm-3. Furthermore, a flexible asymmetric supercapacitor device was fabricated using viscous ionic electrolyte and it was capable to glow a red LED while it was bent in different angles. The methods described here will enhance the study of MXene-based nanohybrid as well as waste material management and cover the usage of biowaste in next-generation supercapacitor electrode materials.