Flexible\nBlack-Phosphorus Nanoflake/Carbon Nanotube Composite Paper for High-Performance\nAll-Solid-State Supercapacitors

Abstract

We\nproposed a simple route for fabrication of the flexible BP nanoflake/carbon\nnanotube (CNT) composite paper as flexible electrodes in all-solid-state\nsupercapacitors. The highly conductive CNTs not only play a role as\nactive materials but also increase conductivity of the hybrid electrode,\nenhance electrolyte shuttling and prevent the restacking between BP\nnanoflakes. The fabricated flexible all-solid-state supercapacitor\n(ASSP) device at the mass proportion of BP/CNTs 1:4 was found to deliver\nthe highest volumetric capacitance of up to 41.1 F/cm³ at\n0.005 V/s, superior to the ASSP based on the bare graphene or BP.\nThe BP/CNTs (1:4) device delivers a rapid charging/discharging up\nto 500 V/s, which exhibits the characteristic of a high power density\nof 821.62 W/cm³, while having outstanding mechanical flexibility\nand high cycling stability over 10 000 cycles (91.5% capacitance retained).\nMoreover the BP/CNTs (1:4) ASSP device still retains large volumetric\ncapacitance (35.7 F/cm³ at the scan rate of 0.005 V/s)\neven after 11 months. In addition, the ASSP of BP/CNTs (1:4) exhibits\nhigh energy density of 5.71 mWh/cm³ and high power density\nof 821.62 W/cm³. As indicated in our work, the strategy\nof assembling stacked-layer composites films will open up novel possibility\nfor realizing BP and CNTs in new-concept thin-film energy storage\ndevices.