Binder-free activated carbon/carbon nanotube paper electrodes for use in supercapacitors

Abstract

Novel inexpensive, light, flexible, and even rollup or wearable devices are required for multi-functional portable electronics and developing new versatile and flexible electrode materials as alternatives to the materials used in contemporary batteries and supercapacitors is a key challenge. Here, binder-free activated carbon (AC)/carbon nanotube (CNT) paper electrodes for use in advanced supercapacitors have been fabricated based on low-cost, industrial-grade aligned CNTs. By a two-step shearing strategy, aligned CNTs were dispersed into individual long CNTs, and then 90 wt%-99 wt% of AC powder was incorporated into the CNT pulp and the AC/CNT paper electrode was fabricated by deposition on a filter. The specific capacity, rate performance, and power density of the AC/CNT paper electrode were better than the corresponding values for an AC/acetylene black electrode. The capacity reached a maximum value of 267.6 F/g with a CNT loading of 5 wt%, and the energy density and power density were 22.5 W·h/kg and 7.3 kW/kg at a high current density of 20 A/g. The AC/CNT paper electrode also showed a good cycle performance, with 97.5% of the original capacity retained after 5000 cycles at a scan rate of 200 mV/s. This method affords not only a promising paper-like nanocomposite for use in low-cost and flexible supercapacitors, but also a general way of fabricating multi-functional paper-like CNT-based nanocomposites for use in devices such as flexible lithium ion batteries and solar cells.

Supercapacitors specialities - Materials review

“…Binder-free activated carbon/carbon nanotube paper electrodes for use in supercapacitors were fabricated in [78]. The specific capacitance reached a maximum value of 267.6 F/g for a loading of 5 wt % of carbon nanotubes.…”

Microwave autoclave synthesized multi-layer graphene/single-walled carbon nanotube composites for free-standing lithium-ion battery anodes

“…The development of such devices implies higher requirements on their battery systems, in which flexibility of the electrodes is essential to enable their bendable features [1][2][3]. Typically, the conventional lithium-ion batteries (LIBs) have electrodes containing metal substrates, which are coated with a mixture of an active material, an electrical conductor, a binder, and a solvent [ 4,5].…”

Carbon Nanomaterials for Flexible Energy Storage

“…This can be achieved by vacuum filtration of the stable suspension containing both CNTs and AC particles. [15,38,66] Experimental results also demonstrated that the flexible composite electrodes have much better performance compared with other electrodes made with traditional approaches. Flexible and binder-free CNTs/AC electrodes containing 95 wt% of AC were able to reach specific capacitance of 268 F/g at 200 mV/s in 6 M KOH.…”

“…Energy density of 22.5 Wh/kg and power density of 7.3 kW/kg, along with remarkable stability of 97.5% retention for 5,000 cycles were also demonstrated. [38] …”