Carbon-modified Na₂Ti₃O₇·2H₂O nanobelts as redox active materials for high-performance supercapacitor

Highlights: • The performance of C/Na-TNBs supercapacitor encapsulated by PDMS has been studied. • Unique layered structure further verifies the charging and discharging mechanism. • Three supercapacitors in series can light 100 green LEDs for about 10 min. The Na₂Ti₃O₇·2H₂O nanobelts (Na-TNBs) with layered structure have been prepared by simple hydrothermal method. The carbon modified Na-TNBs (C/Na-TNBs) supercapacitor has been encapsulated by the flexible and stretching PDMS (poly-dimethylsiloxane), which has flexible and stretching property. The capacitance of the device can attain 459.71 F g⁻¹ at scan rate of 25 mV/S and energy density of 33.2 Wh kg⁻¹ at power density 478 W kg⁻¹ and power density of 2.13 kW kg⁻¹ at energy density 25.36 Wh kg⁻¹. The retention of specific capacitance remains 74.3% after 6000 cycles at high current value of 35 mA. Three supercapacitors in series can light 100 green color commercial light emitting diodes (LEDs) for about 10 min. All these results indicate that the C/Na-TNBs nanomaterial could provide the potential application in high performance supercapacitor.