The mechanical and electrochemical properties of polyaniline-coated carbon nanotube mat

TL;DR

This study investigates the mechanical and electrochemical properties of carbon nanotube-polyaniline composite electrodes, demonstrating their potential for structural energy storage with stable performance after extensive cycling.

Contribution

It introduces a method to manufacture CNT-PANI composite electrodes and provides comprehensive analysis of their properties and durability, highlighting their suitability for energy storage applications.

Findings

Electrode modulus and strength increase with higher CNT volume fraction.

Capacitance increases with higher PANI content.

Properties decrease less than 15% after 1000 charge/discharge cycles.

Abstract

The measured capacitance, modulus and strength of carbon nanotube-polyaniline (CNT-PANI) composite electrodes render them promising candidates for structural energy storage devices. Here, CNT-PANI composite electrodes are manufactured with electrodeposition of PANI onto the bundle network of CNT mats produced via a floating catalyst chemical vapour deposition process. PANI comprises 0% to 30% by volume of the electrode. The composition, modulus, strength and capacitance of the electrodes is measured in the initial state, after the first charge, and after 1000 charge/discharge cycles. Electrode modulus and strength increase with increasing CNT volume fraction; in contrast, the capacitance increases with increasing PANI mass. Charging or cycling reduce the electrode modulus and strength due to a decrease in CNT bundle volume fraction caused by swelling; the electrode capacitance also decreases due to a reduction in PANI mass. A micromechanical model is able to predict the stress-strain response of pre-charged and cycled electrodes, based upon their measured composition after pre-charging and cycling. The electrodes possess up to 63% of their theoretical capacitance, and their tensile strengths are comparable to those of engineering alloys. Their capacitance and strength decrease by less than 15% after the application of 1000 charge/discharge cycles. These properties illustrate their potential as structural energy storage devices.