The K2Ti6O13 nanobeams (K-TNBs) with tunnel structure have been prepared by simple hydrothermal method. To attain the flexible property and the high cycle stability, the carbon absorbed on K-TNBs (C@K-TNBs) supercapacitor (SC) has been encapsulated by the flexible PDMS (polydimethylsiloxane). The solid SC device shows excellent rate capability, high cycle stability and high flexibility at any degrees. The capacitance of the device can attain 301 F g (1) at current of 3 mA, energy density of 26.8 Wh kg (1) at power density 400 W kg (1) and power density of 1.47 kW kg (1) at energy density 16.3 Wh kg (1). The retention of specific capacitance remains 82.7% after 10000 cycles at high current value of 21 mA. Three supercapacitors in series can light 100 green color commercial light emitting diodes (LEDs) for about 16 minutes. All these results indicate that the C@K-TNBs nanomaterial could provide the potential application in high performance supercapacitor. (C) 2017 Elsevier Ltd. All rights reserved.