The development of solid-state electrolytes (SSEs) with high ionic conductivity, outstanding electrochemical window, and promising mechanical strength is a key factor in realizing the commercialization of high energy density solid-state lithium metal batteries (LMBs). Covalent organic frameworks (COFs) are a functional crystalline material with highly customizable molecular networks and one-dimensional channel structures, thus showing great potential applications in SSEs. Herein, we design flexible COF-poly(vinyl ethylene carbonate) (PVEC) (abbreviated as COF-PVEC) composite electrolyte films with excellent ionic conductivity and high mechanical strength, enabling dendrite-free and long-term running solid-state LMBs. Owing to the lithium-philic triazine and carbon–carbon double bonds groups in the COF skeleton, the obtained flexible COF-PVEC shows high ionic conductivity up to 1.11 × 10⁻⁴ S·cm⁻¹ at 40 °C, and enlarged electrochemical window up to 4.6 V (vs. Li⁺/Li) compared with pure PVEC electrolyte. At the same time, the lithium dendrites are efficiently inhibited after discharge–charging cycles, due to the improved Young’s modulus (150 MPa) and ordered channels of COF. Using the various features of COF-PVEC, we assembled a solid-state full battery with LiFePO₄ cathode, which showed superior rate capacity (151.8, 146.2, 139.2, 128.1, 113.7, and 100.8 mAh·g⁻¹ at 0.1, 0.2, 0.5, 1, 1.5, and 2 C, respectively) and excellent long-term cycling stability (over 400 cycles at 1 C). We believe that the COF-based composite electrolyte can become one of the most promising high-performance SSEs for solid-state LMBs.

Development of lead-free halide perovskites that are innocuous and stable has become an attractive trend in resistive random access memory (RRAM) fields. However, their inferior memory properties compared with the leadbased analogs hinder their commercialization. Herein, the lead-free Cs₃Bi₂Br₉ perovskite quantum dot (PQD)-based RRAMs are reported with outstanding memory performance, where Cs₃Bi₂Br₉ quantum dots (QDs) are synthesized via a modified ligand-assisted recrystallization process. This is the first report of applying Cs₃Bi₂Br₉ QDs as the switching layer for RRAM device. The Cs₃Bi₂Br₉ QD device demonstrates nonvolatile resistive switching (RS) effect with large ON/OFF ratio of 10⁵, low set voltage of −0.45 V, as well as good reliability, reproducibility, and flexibility. Concurrently, the device exhibits the notable tolerance toward moisture, heat and light illumination, and longterm stability of 200 days. More impressively, the device shows the reliable light-modulated RS behavior, and therefrom the logic gate operations including “AND” and “OR” are implemented, foreboding its prospect in logic circuits integrated with storage and computation. Such multifunctionality of device could be derived from the unique 2D layered crystal structure, small particle size, quantum confinement effect, and photoresponse of Cs₃Bi₂Br₉ QDs. This work provides the strategy toward the high-performance RRAMs based on stable and eco-friendly perovskites for future applications.