Despite the high energy density of lithium metal batteries (LMBs), their application in rechargeable batteries is still hampered due to insufficient safety. Here, we present a novel flame-retardant solid-state electrolyte based on polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) with nano SiO₂ aerogel as an inert filler but Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZTO) as an auxiliary component to enhance the ion conductivity. The introduction of SiO₂ aerogels imparts the polymer electrolyte with exceptional thermal stability and flame retardancy. Simultaneously, the interaction between hydroxyl groups of SiO₂ particles and PVDF-HFP creates a strong cross-linking structure, enhancing the mechanical strength and stability of the electrolyte. Furthermore, the presence of SiO₂ aerogel and LLZTO facilitates the dissociation of lithium salts through Lewis acid-base interactions, resulting in a high ionic conductivity of 1.01 × 10⁻³ S·cm⁻¹ and a wide electrochemical window of ~ 5.0 V at room temperature for the prepared electrolytes. Remarkably, the assembled Li|Li cell demonstrates the excellent resistance to lithium dendrite and runs stablly for over 1500 h at a current density of 0.25 mA·cm⁻². Thus, we prepare a pouch cell with high safety, which can work normally after short-circuiting under the external folding and cutting.

Flexible power devices play an increasingly crucial role in emerging flexible electronics. To improve the electrochemical performance of flexible power devices, novel electrode structures and new energy-storage systems should be designed. Herein, a novel flexible Li-ion hybrid capacitor (LIC) is designed based on an anode comprising Li₄Ti₅O₁₂ nanoplate arrays coated on carbon textile (LTO/CT) and a cathode comprising a flexible N-doped graphene/carbon-nanotube composite (NGC) film. The LTO/CT anode is fabricated by directly growing Li₄Ti₅O₁₂ nanoplates on CT with robust adhesion using a simple one-pot hydrothermal reaction. Considering the volume of a real-device flexible LIC, the NGC//LTO/CT configuration delivers high volumetric energy and power densities of 2 mWh·cm⁻³ and 185 mW·cm⁻³, respectively. Furthermore, the flexible LIC shows excellent flexibility and electrochemical stability, with extremely small capacity fluctuation under different bending states. This work demonstrates a scalable route to assemble flexible LICs as high-performance power devices.