Ultra-stable sandwich shaped flexible MXene/CNT@Ni films for high performance supercapacitor

MXene exhibits high volume capacity, but poor flexibility and mechanical properties have seriously limited its further applications. To address this issue, a sandwich shaped flexible MXene/CNTs@Ni film has been fabricated via a simple filtration approach, wherein the nickel-electroless plating on CNTs (CNTs@Ni) are utilized as the effective interlayer spacers of MXene nanosheets to stabilize their layer structures. In addition, the optimized MXene/CNTs@Ni film electrode as a binder-free and self-supported electrode exhibits robust mechanical stability and impressive electrochemical properties, especially with a high specific capacitance of 990.8 F cm−3, about 1.4 times and 2.4 times higher than that of MXene/CNTs film electrode and pristine MXene film electrode, respectively. A flexible symmetrical supercapacitor (FSMS) was constructed based on MXene/CNTs@Ni film. Notably, the FSMS owns a high energy density of 14.5 Wh kg−1, a high power density of 2571.4 W kg−1, and a good cycling stability, suggesting its potential application in portable energy technologies.