Electrochemical evaluation of copper pyrophosphate-MXene nanocomposite for supercapacitor application

Ex-situ synthesized copper pyrophosphate (CPP)–MXene nanocomposites were systematically investigated as electrode materials for supercapacitor applications. Electrochemical performance was evaluated for different CPP–MXene ratios (90:10, 70:30, and 50:50), and the 70:30 composite exhibited the highest capacity of 88 mAh/g. The optimized electrode demonstrated stable cycling behavior with a capacity retention of 76.94 % and a coulombic efficiency of 92.16 % over 5000 charge-discharge cycles. To further explore practical applicability, a solid-state asymmetric supercapacitor device was fabricated using the optimized CPP–MXene composite as the cathode and activated carbon as the anode. The device delivered a specific capacitance of 97 F/g at 1 A/g, a specific energy of 34 Wh/kg, and a specific power of 800 W/kg, along with good capacitance retention over long-term cycling. These results confirm that CPP–MXene composite provides a well-balanced combination of capacity, specific energy, specific power, and stability. This suggested that the CPP–MXene composite has a strong potential for energy storage applications. • Ex-situ synthesis of copper pyrophosphate-MXene composites. • The optimized composite (70:30) electrode delivered a specific capacity of 88 mAh/g. • The electrode exhibited good capacity retention (76.94 %) and efficiency (92.16 %). • The asymmetric supercapacitor (ASC) achieved good specific capacitance (97 F/g). • The ASC exhibited good specific energy (34 Wh/kg) and specific power (800 W/kg).