Synergistic Tailoring of Ion–Dipole Interactions and Segmental Dynamics in Fluorinated Ionogels for Low-Temperature Micro-Supercapacitors

Abstract

Polymeric gel electrolytes offer stable ion-transport under mechanical deformation, enabling reliable operation in wearable and flexible energy-storage devices. However, their performance deteriorates notably at low-temperatures due to reduced ionicity and restricted molecular motion within the polymer network. Addressing this challenge requires a rational gel electrolyte design that promotes ion dissociation and transport even at low-temperatures. Here, we propose a synergistic molecular tailoring strategy for copolymer gelators. Fluorinated functional groups are introduced to attenuate the local electrostatic environment, facilitating the dissociation of ion pairs, while side-chain extension creates a more compliant and less temperature-dependent network that preserves ion motion at low-temperatures. Incorporating our ionogel into micro-supercapacitors enables stable electrochemical operation at temperatures more than 30 °C below the limit of typical systems, while maintaining cycling stability. Overall, these results demonstrate that molecularly tailored copolymer networks can effectively mitigate the intrinsic temperature sensitivity of gel electrolytes and establish a broadly applicable design principle for energy-storage devices operating in extreme environments.