Ionically-conductive and stretchable hydrogels are ideally suited for the synthesis of flexible electronic devices. However, conventional hydrogels undergo dehydration at ambient conditions and freeze at subzero temperatures, limiting their functions. As an alternative to counteract these limitations, we propose double network hydrogels that are easily synthesized by a one-step acrylamide (AM) polymerization in the presence of cellulose nanofibrils (CNF) and LiCl. Following molecular dynamics simulation, thermogravimetric and spectroscopic (Raman and low-field nuclear magnetic resonance) analyses, we show that LiCl increases the interactions between the colloidal phase and water molecules, ensuring water holding capability at atmospheric conditions and endowing the hydrogels with freezing tolerance over a wide range of temperatures, from -80 to 25 °C. The synergy between CNF and LiCl is critical in maintaining the mechanical strength of the system, which simultaneously displays high stretchability (∼748 %) and ionic conductivity (2.25 S/m) at low temperatures (-40 °C). As a proof of concept, a flexible supercapacitor comprising the proposed electrolyte hydrogel is demonstrated as a reliable, low-temperature electrochemical device. Our results provide the basis for simple and universally applicable systems that fulfill the requirements of flexible electronics under extreme cold conditions.

离子导电和可拉伸的水凝胶非常适合于柔性电子设备的合成。但是，常规的水凝胶在环境条件下会发生脱水，并在零下温度下冻结，从而限制了它们的功能。作为抵消这些局限性的替代方法，我们提出了在纤维素纳米原纤维（CNF）和LiCl存在下通过一步丙烯酰胺（AM）聚合容易合成的双网络水凝胶。经过分子动力学模拟，热重分析和光谱分析（拉曼和低场核磁共振）分析，我们显示LiCl增强了胶体相与水分子之间的相互作用，确保了在大气条件下的持水能力，并使水凝胶的耐冻性超过温度范围广，-80至25°C。CNF和LiCl之间的协同作用对于维持系统的机械强度至关重要，该系统在低温（-40°C）时同时显示出高拉伸性（〜748％）和离子电导率（2.25 S / m）。作为概念的证明，包含所提出的电解质水凝胶的柔性超级电容器被证明是可靠的低温电化学装置。我们的结果为在极端寒冷条件下满足柔性电子产品要求的简单通用的系统提供了基础。包含提出的电解质水凝胶的柔性超级电容器被证明是一种可靠的低温电化学装置。我们的结果为在极端寒冷条件下满足柔性电子产品要求的简单通用的系统提供了基础。包含提出的电解质水凝胶的柔性超级电容器被证明是一种可靠的低温电化学装置。我们的结果为在极端寒冷条件下满足柔性电子产品要求的简单通用的系统提供了基础。