One-Step Fabrication of Ice-Templated Pure Polypyrrole Nanoparticle Hydrogels for High-Rate Supercapacitors
Muyun Huang, Lü Li, Zhiting Ai, Xinpei Gao, Jiaying Qian, Huanjun Xu, Xiaofang Su, Jifeng Wu, Yanan Gao
Abstract
Conducting polymer hydrogels with high conductivity, excellent electroactivity, and good mechanical strength are desirable for the design of high-performance energy storage devices. However, they suffer from the issue of low porosity, which hinders electrolyte diffusion and leads to poor rate performance. In this work, we developed a one-step, in situ chemical polymerization approach to fabricate a porous pure polypyrrole hydrogel (PPH) with a desirable nanostructure via an ice-templating strategy. This simple synthetic approach offers the PPH tunable porosity, ultrahigh conductivity, and good mechanical strength. Owing to these notable advantages, functioning as a supercapacitor electrode, PPH displays a high specific capacitance of 265 F g–1 (1961 mF cm–2) at 1.35 A g–1 (10 mA cm–2) and maintains 85% capacitance retention even up to 67.6 A g–1 (500 mA cm–2). We also found that PPH without an ice-templated nanostructure possesses poor rate capability due to slow and blocked electrolyte diffusion because of the less-porous nanostructure. This facile, ice-templated strategy to structurally design a porous nanostructure for high-rate performance opens up the possibility for advanced energy storage applications.