Effect of Charge Density on the Mechanical and Electrochemical Properties of Poly (acrylic acid) Hydrogel Electrolytes Based Flexible Supercapacitors
By Khan, Yusuf; Bashir, Shahid; Hina, Maryam; Ramesh, S.; Ramesh, K.; Mujtaba, M. A.; Lahiri, Indranil; Ramesh, S.
Published in Materials Today Communications
Materials Today Communications
2020
Abstract
The conventional hydrogels have lack of structural sites which dissipate energy while applying load, this energy dissipation provides strength to hydrogel structure but due to shortage of energy dissipation mechanism, conventional hydrogels suffer from low stretchability and weak mechanical strength. To tackle this problem, much research has been done to improve the properties of hydrogel. Here, we report double network (DN) hydrogel electrolytes of poly (acrylic acid) synthesized through free radical mechanism. Ammonium persulfate (APS) and N, N-methylene bisacrylamide (MBA) were used as an initiator and crosslinking agent, respectively. Hydrogel electrolytes were prepared by soaking the as-prepared hydrogels into 1 M KCl, 1 M CaCl2, and 1 M FeCl3 salt solutions. Cations (K+, Ca2+, and Fe3+) ionically interacted with carboxylate ions of poly (acrylic acid) network to form double network AA (KCl), AA (CaCl2), and AA (FeCl3) hydrogel electrolytes. The synthesized hydrogel and hydrogel electrolytes were structurally characterized via Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. The surface morphology was observed using field emission scanning electron microscopy. The pore size of the hydrogel (AA) and hydrogel electrolytes was measured by Brunauer- Emmet-Teller (BET). Ionic conductivity study was conducted at room temperature and found that AA (KCl), AA (CaCl2), and AA (FeCl3) had ionic conductivity of 7.8