Hydrogel electrolytes have gained significant attention in the field of flexible supercapacitors for their intrinsic safety, high flexibility, and superior ionic conductivity. However, the water-rich structures of traditional hydrogel electrolytes inevitably cause them to freeze at subfreezing temperatures, which therefore limits the application of flexible supercapacitors at extremely cold temperatures. Herein, an organohydrogel electrolyte was successfully fabricated by displacing a portion of water molecules from hydroxypropyl cellulose/poly­(vinyl alcohol) (HPC/PVA) hydrogel with LiClO4 water/glycerol mixture solution. The introduction of glycerol and inorganic salt into the hydrogel matrix can effectively preclude the ice formation of water at subfreezing temperatures. The flexible supercapacitor comprising the optimal antifreezing organohydrogel electrolyte exhibited excellent mechanical and electrochemical stability at subfreezing temperatures. Even if the temperature decreased to −40 °C, the supercapacitor could also deliver a specific capacitance of 143.6 F g–1 (73.75% of the one delivered at 20 °C) with Coulombic efficiency approaching ∼100%. Meanwhile, the electrochemical performance of the supercapacitor could also be well maintained under different bending conditions. It is believed that this work will play an exemplary role for designing antifreezing gel electrolytes for flexible energy storage devices using at extremely cold environments.

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International audienceCamellia is one of the widely used block ciphers, which has been selected as an international standard by ISO/IEC. In this paper, by exploiting some interesting properties of the key-dependent layer, we improve previous results on impossible differential cryptanalysis of reduced-round Camellia and gain some new observations. First, we introduce some new 7-round impossible differentials of Camellia for weak keys. These weak keys that work for the impossible differential take 3/4 of the whole key space, therefore, we further get rid of the weak-key assumption and leverage the attacks on reduced-round Camellia to all keys by utilizing the multiplied method. Second, we build a set of differentials which contains at least one 8-round impossible differential of Camellia with two FL/FL − 1 layers. Following this new result, we show that the key-dependent transformations inserted in Camellia cannot resist impossible differential cryptanalysis effectively. Based on this set of differentials, we present a new cryptanalytic strategy to mount impossible differential attacks on reduced-round Camellia

Supramolecular polymers (SPs) exhibit intriguing benefits in functional soft materials due to their dynamic bonding feature. However, most SPs can only exist in the solution state and fail to form bulk materials, which limits their applications. Here, we report the fabrication of semi-solid bulk SP materials by using polyoxometalate (POM) nanoclusters as supramolecular cross-linkers to solidify a deep eutectic solvent (DES). The abundant protons and strong hydrogen bonds afforded by POMs enable these SP materials as superprotonic conductive electrolytes with sufficient mechanical strength, showing a proton conductivity more than 1 × 10 À 4 S cm À 1 and a breaking strength exceeding 1 MPa at room temperature. Moreover, the thermodynamic reversibility of the SP electrolytes allows them to form a stable electrode-electrolyte interface by a facile meltinfiltration strategy upon mild heating, which leads to improved performance in supercapacitors. This work presents an innovative DES/POM hybrid system as a promising platform to develop functional supramolecular materials for energy and electronic applications.