Polyethylene oxide (PEO)-based solid-state electrolytes are considered ideal for electrolyte materials in solid-state lithium metal batteries (SSLMBs). However, practical applications are hindered by the lower conductivity and poor interfacial stability. Here, we propose a strategy to construct a three-dimensional (3D) fiber network of metal-organic frameworks (MOFs). Composite solid electrolytes (CSEs) with continuous ion transport pathways were fabricated by filling a PEO polymer matrix in fibers containing interconnected MOFs. This 3D fiber network provides a fast Li⁺ transport path and effectively improves the ionic conductivity (1.36 × 10⁻⁴ S·cm⁻¹, 30 °C). In addition, the network of interconnected MOFs not only effectively traps the anions, but also provides sufficient mechanical strength to prevent the growth of Li dendrites. Benefiting from the advantages of structural design, the CSEs stabilize the Li/electrolyte interface and extend the cycle life of the Li-symmetric cells to 3000 h. The assembled SSLMBs exhibit excellent cycling performance at both room and high temperatures. In addition, the constructed pouch cells can provide an areal capacity of 0.62 mA·h·cm⁻², which can still operate under extreme conditions. This work provides a new strategy for the design of CSEs with continuous structure and stable operation of SSLMBs.

The rational and effective combination of multicomponent materials and ingenious microstructure design for efficient electromagnetic wave (EMW) absorption are still challenging. In this paper, MXene was used as the aerogel matrix, modified with sea urchin-like magnetic Co/N-doped carbon@polyaniline (Co-NC@PANI), gelatin was introduced as the reinforcement phase of the aerogel backbone, and a microwave absorber with high efficiency and excellent performance was successfully prepared. The sea urchin-like Co-NC@PANI not only adjusted the impedance matching of the MXene but also introduced a magnetic loss mode into the composite. The multicomponent interfacial polarization, heterostructure, three-dimensional (3D) lightweight porous structure, and electromagnetic synergy strategy enabled the MXene-based aerogel modified by Co-NC@PANI (MCoP) to exhibit surprising EMW absorption properties. The maximum reflection loss (RL_max) of the aerogel composite reached −62.4 dB, and the effective absorption bandwidth (EAB) reached 6.56 GHz when the loading was only 12%. In addition, through electromagnetic simulation experiments, the change in the electromagnetic field before and after EMW passed through the materials and the distribution of the volume loss density of EMW by the coaxial ring were observed. The coordinated electromagnetic balance strategy in the 3D network provides inspiration for the construction of materials and expands the research direction of lightweight and outstanding microwave absorbers.