Accelerating the ionic transport properties in zwitterionic PAM-based hydrogel for direct liquid fuel cells

Abstract

Direct liquid fuel cells represent a promising energy conversion technology with high energy conversion efficiency and energy density, but the application is limited by the inherent instability and high economic costs of physical membranes. As one of the emerging multifunctional polymer materials, hydrogels offer exceptional and tunable properties in mass transport, mechanical performance, and biocompatibility. Understanding the influence of functional groups on the physicochemical properties of hydrogels and developing high-performance hydrogel materials is crucial to develop high-performance direct liquid fuel cells. Herein, we design and optimize a polyzwitterionic P(AM-SA-MAPTAC) hydrogel with superior mechanical properties, swelling capacity, and mass transport performance. When the hydrogel is utilized as a multifunctional electrolyte, it enables a peak power density of 9.18 mW·cm-2 and limiting current density of 46.95 mA·cm-2. More importantly, the current density shows only a 2.86% performance decay after 100 minutes. This study offers new insights into the design of functional hydrogels and their applications indirect liquid fuel cells.