Flexible capacitor systems with high-performance and stretchable characteristics have been widely concerned due to potential applications in portable and wearable electronics. Herein, we prepared PVA/Carbon nanotube (CNT)@Ni(HCO3)(2) flexible film as supercapacitor electrodes. CNTs is used as charge transfer pathway to enhance the conductivity of polymer and double-layer capacitance. Ni(HCO3)(2) decorated on CNTs provides pseudocapacitance, and PVA matrix provides bendable and stretchable ability. The device achieves a specific capacitance of 143.6 mF cm(-2), and the PVA/CNT@Ni(HCO3)(2) film exhibits tensile strength of 0.37 MPa with elongation at break of 450%. The flexible device with excellent stretchable and bendable ability shows an instant response to the finger bending with the capacitance change more than 35%, which provides the possibility for fabricating novel smart flexible device to monitor human health and motion detection. (C) 2019 The Electrochemical Society.