In by admin

NameMr. A M Mahmudul Hasan
EmailEmail hidden; Javascript is required.
OrganizationUniversity of Florida
PositionGraduate Student
InvitedNo
TypePoster
TopicPMSE/POLY
Title

Ionic Polymer of Intrinsic Microporosity and Their Electrochemical Devices

Author(s)

A M Mahmudul Hasan1, Joshua D. Marquez1, Rupam Roy1, Saptasree Bose2, Kent Kirlikovali2, Omar K. Farha2, and Austin M. Evans1

Author Location(s)

1Department of Chemistry, Butler Polymer Research Laboratory, University of Florida, 2Department of Chemistry, Northwestern University

Abstract

Polymers of intrinsic microporosity (PIM) are desirable for electrochemical devices because they are synthetically tunable, easily processable, and rapidly accessible by ionic species. However, most PIMs are not redox-active. Here, I show a new class of ionic and redox-active PIM that takes advantage of viologen subunits to overcome this limitation.  The straightforward processing of this material allows us to produce high-functioning supercapacitor electrodes without the need for conductive additives or binders. Electrochemical impedance spectroscopy and galvanostatic charge-discharge cycling measurements performed on our viologen PIM and a non-porous viologen polymer reveal that the high energy and power density are both due to the ability of ions to rapidly access the ionic PIM. The high performance of this material is directly related to its large accessible surface area (200 m2 g‑1), as evaluated by porosimetry measurements.  In 0.1 M H2SO4 electrolyte, a pseudocapacitive energy density of 315 F g-1 is observed, whereas in 0.1 M Na2SO4, a purely capacitive energy density of 250 F g-1 is obtained. In both cases, this capacity is retained over 10,000 charge-discharge cycles. These findings motivated us to create a prototype symmetric two-electrode capacitor, which had an areal capacitance of 193 mF cm-2 that was virtually unchanged after 2000 charging-discharging cycles. The constructed device also undergoes a reversible color change when exposed to two distinct redox potentials. The enhanced ion transport within viologen PIMs gives a rapid and highly efficient color change. This discovery implies that redox-active PIMs may also exhibit excellent performance in other electrochemical devices, including chemical sensors and ion-separation membranes.

Date05/30/2024