Fabrication of flexible and bendable solid state symmetric supercapacitor based on carbon black intercalated MXene

Although Ti₃C₂T_x MXene has emerged as a promising electrode material for electrochemical supercapacitors, it suffers from limited pseudocapacitance caused by the aggregation of MXene layers, which reduces the number of available active sites. Resolving the restacking issue by increasing the number of accessible adsorption sites for electrolyte ions can help to improve charge storage. Therefore, this study focuses on avoiding the re-stacking of MXene layers by intercalating carbon black (CB) nanosheets, which avoids restacking and raises the conductivity and number of accessible adsorption sites. Physicochemical characterizations of MXene and MXene/CB composites are performed to synthesize the MXene/CB composite. Successful improvement in the charge storage capability of the fabricated composite, attributable to the inclined interlayer spacing of MXene with the intercalation of highly conductive CB nanosheets is studied using cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The synergy between 2D-MXene and conductive CB is responsible for the fabricated material's enhanced specific capacitance (383 F g⁻¹). In addition, MXene/CB is used to fabricate a symmetric supercapacitor device. The symmetric supercapacitors device exhibits high areal capacitance (138.75 mF/cm²), energy density (12.33 mWh/cm²), power density (2212 mW/cm²), and 86.14 and 78.7 % capacitance retentions after 3000 and 5000 cycles, respectively, which can be attributed to the maintained interlayer spacing between the MXene sheets using CB. The developed device has highly flexible (60 N) and bendable (up to 90°) properties. This study introduces a sustainable and effective strategy to overcome MXene restacking challenges, which offers new avenues for environmentally friendly and scalable energy storage solutions.