Flexible of multiwalled carbon nanotubes/manganese dioxide nanoflake textiles for high-performance electrochemical capacitors

Abstract

• Hierarchical MnO 2 nanoflakes are conformally deposited on CNTs based textiles. • The electrodeposition mechanism is investigated by time-dependent experiments. • The textiles show excellent flexibility and structural integrity after 2000 cycles. • A slight capacitance decrease even as the textiles vertically folded. In this paper, an ultrathin layer of acid treated multiwalled carbon nanotubes (CNTs) are conformally wrapped on everyday cotton textiles for subsequently controlled electrodeposition of MnO 2 nanoflakes. The general morphology and detailed microstructure of the as-prepared composites are characterized and the formation mechanism is investigated by time-dependent experiments. Such conductive textiles show outstanding flexibility and strong adhesion between the CNTs and the textiles of interest. Supercapacitors made from these ternary conductive textiles show high specific capacitance up to 247 F·g −1 at 1 A·g −1 . A capacity retention of 94.7% can be maintained at 2000 continuous charge-discharge cycles, after which the textiles electrode essentially maintained its whole structural integrity. The discharge curves remain unchanged with a slight capacitance decrease even under vertical folding condition. All these demonstrate that hybrid flexible electrode of MnO 2 and conductive textile is an effective strategy towards high-energy supercapacitors and may provide a promising design direction for optimizing the electrochemical performance of insulating metal oxide based on electrode materials.