Constructing multifunctional aerogels that simultaneously integrate electromagnetic microwave (EMW) absorption, flame retardancy, acoustic damping, and thermal protection remains a formidable challenge due to inherent trade-offs in structural design and compositional synergy. Herein, we propose a hierarchical assembly and controlled carbonization strategy to fabricate MXene-reinforced MOF-on-MOF derived carbon aerogels (Z@F_xN_y-M/CA), wherein the Fe³⁺/Ni²⁺ molar ratio is precisely tuned to tailor the microstructure, defect chemistry, and interfacial characteristics. This design enables a unique synergistic interplay between a conductive MXene network, defect-rich carbon frameworks, and Fe/Co/Ni-derived magnetic components, collectively realizing efficient EMW attenuation via coupled conduction loss, polarization relaxation, and magnetic resonance. Remarkably, the optimized aerogel achieves an outstanding minimum reflection loss (RL_min) of -60.36 dB and a broad effective absorption bandwidth (EAB) of 5.06 GHz, outperforming most state-of-the-art absorbers. Beyond EMW absorption, the aerogel exhibits exceptional fire safety, with over 50% reduction in peak heat release rate (pHRR) and total heat release (THR), along with suppressed smoke emission and the formation of a dense graphitized char layer. Furthermore, it delivers superior acoustic damping with a noise reduction coefficient (NRC) of 0.66 and efficient thermal management capability. Such integrated multifunctionality is intrinsically linked to the finely engineered pore architecture, abundant heterogeneous interfaces, and compositionally modulated Fe/Co/Ni-derived phases. This work presents a paradigm-shifting MOF-on-MOF strategy for designing next-generation lightweight aerogels that harmoniously integrate EMW absorption, flame retardancy, thermal insulation, and acoustic protection, offering new insights into structure–property relationships in multimetal-derived multifunctional materials.

The widespread use of lithium batteries has led to frequent fire hazards, which significantly threaten both human lives and property safety. One of the primary challenges in enhancing the fire safety of lithium batteries lies in the flammability of their organic components. As electronic devices continue to proliferate, the integration of liquid electrolytes and separators has become common. However, these components are prone to high volatility and leakage, which limits their safety. Fortunately, recent advancements in solid-state and gel electrolytes have demonstrated promising performance in laboratory settings, providing solutions to these issues. Typically, improving the flame retardancy and fire safety of lithium batteries involves careful design of the formulations or molecular structures of the organic materials. Moreover, the internal interfacial interactions also play a vital role in ensuring safety. This review examines the innovative design strategies developed over the past 5 years to address the fire safety concerns associated with lithium batteries. Future advancements in the next generation of high-safety lithium batteries should not only focus on optimizing component design but also emphasize rigorous operational testing. This dual approach will drive further progress in battery safety research and development, enhancing the overall reliability of lithium battery systems.

The physicochemical properties of metal–organic frameworks (MOFs) are closely dependent on the topology, pore characteristics, and chemical composition, which can be tuned through targeted design. Relative to direct synthesis, the post-synthesis methods of MOFs, including ion exchange, ligand replacement as well as destruction, provide a significant increase in their application range and potential. A method based on the coordination bond cleavage of MOFs has been proved to be very effective in modulating the structure and was evaluated for its application in the flame retardant field. Herein, the construction of peculiar MOF structures is categorized based on flame-retardant features through the cleavage of coordination bonds at the molecular level, and the corresponding MOFs exhibit superior flame-retardant and smoke-suppressing properties. Different approaches are highlighted to achieve coordination bond breaking to modulate MOFs properties, involving chemical composition, topology, and pore structure. This review systematically summarizes and generalizes the direct construction of high-efficiency MOF-based flame retardants based on the structure–activity relationship and their further functionalization through coordination bond cleavage, as well as the associated challenges and prospects. It is also hoped that this work will quickly guide researchers through the field and inspire their next studies.