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Windows are the least energy efficient part of the buildings, as building accounts for 40% of global energy consumption. Traditional smart windows can only regulate solar transmission, while all the solar energy on the window is wasted. Here, for the first time, the authors demonstrate an energy saving and energy generation integrated smart window (ESEG smart window) in a simple way by combining louver structure solar cell, thermotropic hydrogel, and indium tin oxides (ITO) glass. The ESEG smart window can achieve excellent optical properties with ≈90% luminous transmission and ≈54% solar modulation, which endows excellent energy saving performance. The outstanding photoelectric conversion efficiency (18.24%) of silicon solar cells with louver structure gives the smart window excellent energy generation ability, which is more than 100% higher than previously reported energy generation smart window. In addition, the solar cell can provide electricity to for ITO glass to turn the transmittance of hydrogel actively, as well as the effect of antifreezing. This work offers an insight into the design and preparation together with a disruptive strategy of easy fabrication, good uniformity, and scalability, which opens a new avenue to realize energy storage, energy saving, active control, and antifreezing integration in one device. The authors develop a revolutionary smart window with a multi‐layer louver structure, containing a silicon solar cell, thermotropic hydrogel, and ITO active layer, which combine both an energy saving and energy generation ability (ESEG smart window) with leverages high solar energy modulation together with high photoelectric conversion efficiency (PCE).

Rechargeable aqueous zinc‐ion batteries (ZIBs) have been considered as a promising candidate for the large‐scale energy storage device owing to their low cost and high safety. However, the practical application of aqueous ZIBs at low temperature environment is hindered by the freezing aqueous electrolytes, which leads to a sharp drop in ionic conductivity, and thereby a rapid deterioration of battery performance. Herein, a chaotropic salt electrolyte based on low concentration aqueous Zn(ClO4)2 with superior ionic conductivity under low temperature (4.23 mS/cm at −50°C) is reported. The anti‐freezing methodology introduced here is completely different from conventional freeze‐resistant design of using “water‐in‐salt” electrolyte, cosolvents, or anti‐freezing agent additives strategy. Experimental analysis and molecular dynamics simulations reveal that the as‐prepared Zn(ClO4)2 electrolyte possesses faster ionic migration compared with other commonly used Zn‐based salts (i.e., Zn(CF3SO3)2 and ZnSO4) electrolyte. It is found that Zn(ClO4)2 electrolyte can suppress the ice crystal construction by forming more hydrogen bonds between solute ClO4− and solvent H2O molecules, thus leading to a superior anti‐freezing property. The fabricated ZIBs using this aqueous electrolyte exhibits a dramatically enhanced specific capacity, remarkable rate capability, and great cycling stability over a wide temperature range, from −50 to 25°C. The aqueous ZIBs also exhibit an outstanding energy density of 238.4 Wh/kg without compromising the power density (7.9 kW/kg) under −20°C. Moreover, the assembled aqueous ZIBs can also cycle stably over 1000 cycles at an ultra‐low −50°C. The high‐safety and cost‐effective chaotropic salt electrolyte presented here is a promising strategy for low temperature energy storage application. A cost‐effective, anti‐freezing, and high ionic conductivity Zn(ClO4)2 chaotropic salt electrolyte is discovered and applied in low‐temperature aqueous zinc‐ion battery.

Elastic hydrogel is a promising material category for designing biological muscles, repairable building materials, flexible electronic devices, and vulcanized rubber substitutes, which is required to have a long life, good self‐healing performance and extreme temperature tolerance. Herein, a super‐elastic mineral hydrogel is developed with long‐lasting moisture, based on dynamic physical crosslinking between hydrated calcium ion clusters and amide groups of polyacrylamide (PAM). The complex hydrogel exhibits a super stretchability of 13 600% at room temperature, and can maintain the super flexibility in a wide temperature range of −40–50 °C or for a long period of 28 days. Particularly, the soft material cannot be ignited under an open flame at 400–500 °C, because of coupling dual flame retardant mechanisms containing the endothermic effect of liquid water evaporation and the barrier effect of calcium mineral salt on oxygen. In conclusion, the novel complex hydrogel with excellent tensile property, stability in extreme temperature or long operating time, and flame retardancy may become a promising candidate in the fields of agriculture, food, construction, medicine, and machinery. Dynamic physical crosslinking of calcium (II) with in situ polymerized polyacrylamide provides a new mechanism for stress/energy dispersion of soft materials during stretching. As‐prepared complex hydrogel exhibits stable mechanical performance for a long‐term or under extreme temperature, and has ideal flame‐retardant ability due to the water‐locking effect of calcium (II) and barrier effect on oxygen.

The requirement for cryogenic supramolecular self‐assembly of amphiphiles in subzero environments is a challenging topic. Here, the self‐assembly of lamellar lyotropic liquid crystals (LLCs) are presented to a subzero temperature of −70 °C. These lamellar nanostructures are assembled from specifically tailored ultra‐long‐chain surfactant stearyl diethanolamine (SDA) in water/glycerol binary solvent. As the temperature falls below zero, LLCs with a liquid‐crystalline Lα phase, a tilted Lβ phase, and a new folded configuration are obtained consecutively. A comprehensive experimental and computational study is performed to uncover the precise microstructure and formation mechanism. Both the ultra‐long alkyl chain and head group of SDA play a crucial role in the formation of lamellar nanostructures. SDA head group is prone to forming hydrogen bonds with water, rather than glycerol. Glycerol cannot penetrate the lipid layer, which mixes with water arranging outside of the lipid bilayer, providing an ideal anti‐freezing environment for SDA self‐assembly. Based on these nanostructures and the ultra‐low freezing point of the system, a series of novel cryogenic materials are created with potential applications in extremely cold environments. These findings would contribute to enriching the theory and research methodology of supramolecular self‐assembly in extreme conditions and to developing novel anti‐freezing materials. Anti‐freezing lamellar lyotropic liquid crystals with temperature tolerance to −70 °C are realized through a supramolecular self‐assembly of an amphiphile in water/glycerol binary solvent. As temperature falls below 0 °C, crystals with Lα phase, tilted Lβ phase, and a new configuration are obtained consecutively. The results enrich the understanding of supramolecular self‐assembly in extreme environment, and may be useful to create novel materials.

Electric‐fish‐inspired hydrogel‐based power sources offer a promising platform for powering soft, wearable, and implantable electronics due to their compliance, biocompatibility, and biodegradability. They typically consist of high‐ and low‐salinity gel layers separated by anion‐ and cation‐selective gel compartments, generating an electric potential that emulates the diffusion‐based energy mechanisms of electrocytes in electric fish. However, their development has been hindered by high internal resistance, limited power density, and poor environmental stability. Here, a scalable layer‐by‐layer spin‐coating strategy is introduced to fabricate hydrogel electrocytes with precise thickness control, yielding 106.1 µm‐thick units comparable to biological electrocytes. This thin architecture significantly reduces resistance and enables high instantaneous power density (44.0 kW m−3) with low area‐normalized resistance (2.0 × 10−3 Ω m2.). By tailoring the hydrogel composition with a glycerol–carboxylated chitosan mixture, long‐term hydration (>98.7% after 120 h at 60% RH) and antifreezing performance down to −80 °C are achieved without encapsulation. Furthermore, varying layer thickness provides tunable energy density, while integration of PEDOT:PSS hydrogel electrodes preserves material compliance and yields robust, ready‐to‐use power systems. These advances overcome critical barriers in hydrogel‐based energy storage, establishing a versatile, scalable pathway toward stable, bioinspired power sources for next‐generation wearable, implantable, and autonomous devices. This study presents thin, environmentally stable hydrogel power sources inspired by electric fish. Made using layer‐by‐layer spin‐coating with glycerol‐enhanced solutions, they offer precise layer control, long‐term hydration, and anti‐freezing stability. The devices achieve a high‐power density of 44 kW m‒3, low resistance, and are biocompatible, making scalable, wearable, and implantable hydrogel‐based energy systems are possible.

HighlightsA class of hydrogel electrolytes that couple high adhesion and anti-freezing properties is developed.Zn/Li hybrid capacitors based on the hydrogel electrolyte can tolerate low temperatures and accommodate dynamic deformations across a temperature range of 25 to − 60 °C.This work highlights an advancement for promoting next-generation energy storage system with low-temperature capability and mechanical durability.Solid-state zinc-ion capacitors are emerging as promising candidates for large-scale energy storage owing to improved safety, mechanical and thermal stability and easy-to-direct stacking. Hydrogel electrolytes are appealing solid-state electrolytes because of eco-friendliness, high conductivity and intrinsic flexibility. However, the electrolyte/electrode interfacial contact and anti-freezing properties of current hydrogel electrolytes are still challenging for practical applications of zinc-ion capacitors. Here, we report a class of hydrogel electrolytes that couple high interfacial adhesion and anti-freezing performance. The synergy of tough hydrogel matrix and chemical anchorage enables a well-adhered interface between hydrogel electrolyte and electrode. Meanwhile, the cooperative solvation of ZnCl2 and LiCl hybrid salts renders the hydrogel electrolyte high ionic conductivity and mechanical elasticity simultaneously at low temperatures. More significantly, the Zn||carbon nanotubes hybrid capacitor based on this hydrogel electrolyte exhibits low-temperature capacitive performance, delivering high-energy density of 39 Wh kg−1 at −60 °C with capacity retention of 98.7% over 10,000 cycles. With the benefits of the well-adhered electrolyte/electrode interface and the anti-freezing hydrogel electrolyte, the Zn/Li hybrid capacitor is able to accommodate dynamic deformations and function well under 1000 tension cycles even at −60 °C. This work provides a powerful strategy for enabling stable operation of low-temperature zinc-ion capacitors.

Hydrogels are soft–wet materials with a hydrophilic three-dimensional network structure offering controllable stretchability, conductivity, and biocompatibility. However, traditional conductive hydrogels only operate in mild environments and exhibit poor environmental tolerance due to their high water content and hydrophilic network, which result in undesirable swelling, susceptibility to freezing at sub-zero temperatures, and structural dehydration through evaporation. The application range of conductive hydrogels is significantly restricted by these limitations. Therefore, developing environmentally tolerant conductive hydrogels (ETCHs) is crucial to increasing the application scope of these materials. In this review, we summarize recent strategies for designing multifunctional conductive hydrogels that possess anti-freezing, anti-drying, and anti-swelling properties. Furthermore, we briefly introduce some of the applications of ETCHs, including wearable sensors, bioelectrodes, soft robots, and wound dressings. The current development status of different types of ETCHs and their limitations are analyzed to further discuss future research directions and development prospects.

We present green organohydrogel‐based stretchable (up to 700% strain), transparent, and room‐temperature O2 sensors with impressive performance, including drying and freezing tolerances, high sensitivity, broad detection range (100 ppm‐100%), long‐term stability, low theoretical detection limit (0.585 ppm), linearity, and the capability to real‐time monitor human respiration by directly attaching on human skin. A facile solvent replacement approach is employed to partially exchange water with natural and edible xylitol/sorbitol molecules, generating stable, green and tough organohydrogels. Compared with the pristine hydrogel counterpart, the organohydrogel‐based O2 sensors feature higher stability, prolonged life time (140 days) and the ability to work over a wide range of temperatures (−38 to 65°C). The O2 sensing mechanism is elucidated by investigating the redox reactions occurred at the electrode‐hydrogel interface. This work develops a facile strategy to fabricate stretchable, transparent, and high‐performance O2 sensor using stable and green organohydrogels as novel transducing materials for practical wearable applications. Natural and edible sugar alcohols (xylitol/ sorbitol) are exploited to fabricate ultrastretchable, anti‐drying, anti‐freezing, transparent, and green organohydrogels‐based oxygen sensors with high sensitivity, broad detection range (100 ppm‐100%), selectivity, stability (140 days), linearity, and a broad working temperature range (−38 to 65°C). The stretchable O2 sensor can be deployed as wearable epidermal device for continuous and real‐time breath monitoring.

Soft and conductive materials are highly desirable for wearable electronics. In particular, anti‐freezing, long‐water retention, and highly conductive gels with Young's modulus matching that of biological tissues, show promise in bioelectronics. Herein, soft organohydrogels obtained by mixing poly (3,4‐ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS), ethylene glycol (EG), and tannic acid (TA) are reported. The PEDOT/EG/TA organohydrogels exhibit a low compressive Young's modulus of ≈20 kPa, a conductivity of ≈6 S cm−1, as well as anti‐freezing and water retention properties. Epidermal patch electrodes prepared using the PEDOT/EG/TA gel exhibit low skin–electrode impedance at low frequency (1–100 Hz) and high‐quality electrocardiography (ECG) and electromyography signal recordings. Moreover, these gels demonstrate long‐term stability with high ECG recording quality after being placed under ambient conditions for seven days. Soft gels obtained from poly (3,4‐ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS), ethylene glycol (EG), and tannic acid (TA) exhibit a low compressive Young's modulus (≈7 kPa), long‐water retention, and anti‐freezing properties. Epidermal patch electrodes fabricated using the PEDOT/EG/TA gel demonstrate high‐quality electrocardiography (ECG) and electromyography (EMG) signal recordings and human–machine interfaces use.

The application of portable aluminum‐air batteries (AABs) in extreme environments is an inevitable demand for future development. Aqueous electrolyte freezing is a major challenge for low‐temperature operations. Conventionally, enlightened by the organic system in metal ion batteries, blindly increasing the concentration is regarded as an efficient technique to reduce the freezing point (FP). However, the underlying contradiction between the adjusting mechanism of the FP and OH− transportation is ignored. Herein, the aqueous alkali solution of CsOH is researched as a prototype to disclose the intrinsic conductive behavior and related solvent structure evolution. Different from these inorganic electrolyte systems, the concept of a critical anti‐freezing concentration (CFC) is proposed based on a specific temperature. The relationship between hydrogen bond reconstruction and de‐solvation behavior is analyzed. A high conductivity is obtained at −30 °C, which is also a recorded value in an intrinsic aqueous AAB. The homogenous dissolution of the Al anode is also observed. As a general rule, the CFC concept is also applied in both the KOH and NaOH systems. The intrinsic conductive behavior and solvent structure evolution of CsOH are studied. With the decrease of the CsOH, the HB reconstruction and the Cs+ desolvation are occurred. At the CFC, Cs+ has a sparse solvated structure that is attributed to the decreased Cs+‐OH− and weak non‐HB. The OH− in the first shell layer of Cs+ can escape easily and transfer faster, which can be sufficiently diffused to generate homogeneous corrosion.