1f:T413,Maintaining fast charging capability at low temperatures represents a significant challenge for supercapacitors. The performance of conventional porous carbon electrodes often deteriorates quickly with the decrease of temperature due to sluggish ion and charge transport. Here we fabricate a 3D-printed multiscale porous carbon aerogel (3D-MCA) via a unique combination of chemical methods and the direct ink writing technique. 3D-MCA has an open porous structure with a large surface area of ∼1750 m² g^-1. At -70 °C, the symmetric device achieves outstanding capacitance of 148.6 F g^-1 at 5 mV s^-1. Significantly, it retains a capacitance of 71.4 F g^-1 at a high scan rate of 200 mV s^-1, which is 6.5 times higher than the non-3D printed MCA. These values rank among the best results reported for low temperature supercapacitors. These impressive results highlight the essential role of open porous structures for preserving capacitive performance at ultralow temperatures.20:T4c7,It is a challenge to realize high strength, toughness, and energy storage, as well as excellent capacitive self-recovery, fatigue-resistant, and self-healing performances simultaneously in a single all-in-one supercapacitor aiming for wearable electronics. Herein, based on the self-crosslinking and molecular template, a supramolecular poly(vinyl alcohol)/poly (N-hydroxyethyl acrylamide) (PVA/PHEA) hydrogel electrolyte (HGE) decorated by polyaniline (PANI) was prepared by in situ rapid polymerization of high-concentration aniline on the PVA/PHEA gel containing H₂SO₄. The multiple hydrogen bonds, rapid polymerization, and decoration endowed PANI-decorated PVA/PHEA HGE-based all-in-one flexible supercapacitor with the integrated high performances, which include high specific capacitance, good cycling stability, high strength, excellent toughness, rapid self-recovery, excellent fatigue-resistant, and self-healing capabilities, as well as high capacitance retention during or after the large deformations or after the self-healing. Thus, the current work presents a novel and promising strategy to design the integrated high-performance supercapacitors aiming for wearable electronics.21:T535,We demonstrate stable hybrid electrochemical energy storage performance of a redox-active electrolyte, namely potassium ferricyanide in aqueous media in a supercapacitor-like setup. Challenging issues associated with such a system are a large leakage current and high self-discharge, both stemming from ion redox shuttling through the separator. The latter is effectively eliminated when using an ion exchange membrane instead of a porous separator. Other critical factors toward the optimization of a redox-active electrolyte system, especially electrolyte concentration and volume of electrolyte, have been studied by electrochemical methods. Finally, excellent long-term stability is demonstrated up to 10 000 charge/discharge cycles at 1.2 and 1.8 V, with a broad maximum stability window of up to 1.8 V cell voltage as determined via cyclic voltammetry. An energy capacity of 28.3 Wh/kg or 11.4 Wh/L has been obtained from such cells, taking the nonlinearity of the charge-discharge profile into account. The power performance of our cell has been determined to be 7.1 kW/kg (ca. 2.9 kW/L or 1.2 kW/m(2)). These ratings are higher compared to the same cell operated in aqueous sodium sulfate. This hybrid electrochemical energy storage system is believed to find a strong foothold in future advanced energy storage applications.

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