Hybrid supercapacitors have shown great potentials to fulfill the demand of future diverse applications such as electric vehicles and portable/wearable electronics. In particular, aqueous zinc‐ion hybrid supercapacitors (ZHSCs) have gained much attention due to their low‐cost, high energy density, and environmental friendliness. Nevertheless, typical ZHSCs use Zn metal anode and normal liquid electrolyte, causing the dendrite issue, restricted working temperature, and inferior device flexibility. Herein, a novel flexible Zn‐ion hybrid supercapacitor (FZHSC) is developed by using activated carbon (AC) anode, δ‐MnO₂ cathode, and innovative PVA‐based gel electrolyte. In this design, heavy Zn anode and its dendrite issue are avoided and layered cathode with large interlayer spacing is employed. In addition, flexible electrodes are prepared and integrated with an anti‐freezing, stretchable, and compressible hydrogel electrolyte, which is attained by simultaneously using glycerol additive and freezing/thawing technique to regulate the hydrogen bond and microstructure. The resulting FZHSC exhibits good rate capability, high energy density (47.86 Wh kg⁻¹; 3.94 mWh cm⁻³), high power density (5.81 kW kg⁻¹; 480 mW cm⁻³), and excellent cycling stability (~91% capacity retention after 30 000 cycles). Furthermore, our FZHSC demonstrates outstanding flexibility with capacitance almost unchanged even after various continuous shape deformations. The hydrogel electrolyte still maintains high ionic conductivity at ultralow temperatures (≤−30°C), enabling the FZHSC cycled well, and powering electronic timer robustly within an all‐climate temperature range of −30~80°C. This work highlights that the promising Zn metal‐free aqueous ZHSCs can be designed with great multifunctionality for more practical application scenarios.

This review overviews the recent advances in novel electrode materials of ASIBs/APIBs, the operation mechanism of representative materials, and new findings based on the preparation and modification approaches.

All-solid-state lithium batteries (ASSLBs) employing Li-rich layered oxide (LLO) cathodes are regarded as promising next-generation energy storage systems owing to their outstanding energy density and intrinsic safety. Polymer-in-salt solid electrolytes (PISSEs) offer advantages such as high room-temperature ionic conductivity, enhanced Li anode interfacial compatibility, and low processing costs; however, their practical deployment is hindered by poor oxidative stability especially under high-voltage conditions. In this study, we report the rational design of a bilayer electrolyte architecture featuring an in situ solidified LiClO₄-doped succinonitrile (LiClO₄–SN) plastic–crystal interlayer between a Li_1.2Mn_0.6Ni_0.2O₂ (LMNO) cathode and a poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)-based PISSE. This PISSE/SN–LiClO₄ configuration exhibits a wide electrochemical stability window up to 4.7 V vs. Li⁺/Li and delivers a high ionic conductivity of 5.68 × 10⁻⁴ S cm⁻¹ at 25 °C. The solidified LiClO₄-SN layer serves as an effective physical barrier, shielding the PVDF-HFP matrix from direct interfacial contact with LMNO and thereby suppressing its oxidative decomposition at elevated potentials. As a result, the bilayer polymer-based cells with the LMNO cathode demonstrate an initial discharge capacity of ∼206 mAh g⁻¹ at 0.05 C and exhibit good cycling stability with 85.7% capacity retention after 100 cycles at 0.5 C under a high cut-off voltage of 4.6 V. This work not only provides a promising strategy to enhance the compatibility of PVDF-HFP-based electrolytes with high-voltage cathodes through the facile in situ solidification of plastic interlayers but also promotes the application of LMNO cathode material in high-energy ASSLBs.

All-solid-state lithium batteries (ASSLBs) employing Li-rich layered oxide (LLO) cathodes are regarded as promising next-generation energy storage systems owing to their outstanding energy density and intrinsic safety. Polymer-in-salt solid electrolytes (PISSE) offer advantages such as low processing costs, high ionic conductivity, and good anode compatibility; however, their practical deployment is hindered by poor oxidative stability especially under high-voltage. In this study, we report the rational design of a bilayer electrolyte architecture featuring an in situ solidified LiClO₄-doped succinonitrile (LiClO₄–SN) plastic-crystal interlayer between a Li₁.₂Mn₀.₆Ni₀.₂O₂ (LMNO) cathode and a PVDF-HFP-based PISSE. This PISSE/SN–LiClO₄ configuration exhibits a wide electrochemical stability window up to 4.7 V vs. Li+/Li and delivers a high ionic conductivity of 2.38 × 10-4 S cm-1 at 25 °C. The solidified LiClO₄-SN layer serves as an effective physical barrier, shielding the PVDF-HFP matrix from direct interfacial contact with LMNO and thereby suppressing its oxidative decomposition at elevated potentials. As a result, the bilayer polymer-based cells with LMNO cathode demonstrate an initial discharge capacity of ∼206 mAh g-1 at 0.05 C and exhibit good cycling stability with 85.7% capacity retention after 100 cycles at 0.5 C under a high cut-off voltage of 4.6 V. This work not only provides a promising strategy to enhance the compatibility of PVDF-HFP-based electrolytes with high-voltage cathodes through the facile in-situ solidification of plastic interlayers but also promotes the application of LMNO cathode material in high-energy ASSLBs.