Highly flexible, tailorable and all-solid-state supercapacitors from carbon nanotube–MnOx composite films

Carbon nanotube (CNT) films are promising materials for constructing highly flexible composites for supercapacitor electrodes. Here, we prepared composite films with a sandwich structure and outstanding electrochemical properties by electrodepositing manganese oxide (MnOx) on the flexible CNT macrofilms. All-solid-state supercapacitors were then fabricated from the CNT–MnOx composite films using poly(vinylalcohol)–potassium hydroxide as the gel electrolyte. The supercapacitors have a high performance with a specific capacitance of 73.4 F g−1 and an energy density of 6.2 W h kg−1. The supercapacitors also exhibit high flexibility and stability under bending and kneading. When cut into small parts, the supercapacitor fragments can still work independently. The highly flexible and tailorable supercapacitors have great potential in flexible electronics in the future.