the mechanical and electrochemical properties of polyaniline coated carbon nanotube mat

• DOI: 10.48550/arxiv.2106.09097
• Publication Date: 2021-09-01
• Authors: Changshin Jo; Changshin Jo; Michael De Volder; Wei Tan; Wei Tan; Joe C. Stallard; Norman A. Fleck
• Keywords: Polyaniline; Electrochemical properties; Carbon nanotubes; FOS: Physical sciences; Mechanical properties; Physics - Applied Physics; Applied Physics (physics.app-ph); 02 engineering and technology; Pseudocapacitor; 0210 nano-technology; 7. Clean energy

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.