Polymer electrolytes are envisioned to be promising alternatives to their liquid counterparts in lithium-ion batteries as they are able to address electrolyte inflammability and leakage issues. However, polymer electrolytes usually suffer from cracks or breakage, which could lead to short circuits and bring severe safety issues. Herein, we propose a paradigm to address these problems in which the polymer electrolyte is formed by a physically cross-linked network via ureidopyrimidinone (UPy) containing brush-like poly(ethylene glycol) chains. The formed novel polymer electrolyte is flexible and able to provide fast intrinsic self-healability and high stretchability. It can heal the cut damage within 2 hours under ambient conditions without any external stimulus and can be stretched to more than 20 times its length without breaking. Furthermore, the novel polymer electrolyte exhibits excellent interfacial stability with electrodes, resulting in high performance batteries with stable reversible electrochemical reaction and cycling.

A synergistic enhancement effect of PFR-fRGO and Al ₂ O ₃ on the flame resistance and thermal conductivity of epoxy-based composites.

A novel supramolecular network-reinforced and self-healing composite polymer electrolyte (SHCPE) is designed and fabricated via the incorporation of ureido-pyrimidinone (UPy)-functionalized SiO₂ (SiO₂–UPy) into the polymer matrix containing UPy units. The bonded UPy groups on SiO₂ could form supramolecular networks with the polymer via the interactions of quadruple hydrogen bonding. Benefitting from the supramolecular interactions, the fillers of SiO₂–UPy are able to uniformly disperse and reduce the agglomeration. As a result, the interphase between SiO₂ and the polymer matrix, which is crucial to provide a fast conduction channel for lithium ions, is increased. Consequently, the SHCPE exhibits an enhanced ionic conductivity of 8.0 × 10⁻⁵ S cm⁻¹ at 30 °C compared with that of the CPE blended with pristine SiO₂. More importantly, the self-healing and mechanical properties of the SHCPE are simultaneously improved due to the increase of physically cross-linked sites in the polymer matrix. Owing to these outstanding properties, the lithium-ion batteries fabricated using the SHCPE exhibit stable cycling performance.

The growing demands for energy storage systems, electric vehicles, and portable electronics have significantly pushed forward the need for safe and reliable lithium batteries. It is essential to design functional separators with improved mechanical and electrochemical characteristics. This review covers the improved mechanical and electrochemical performances as well as the advancements made in the design of separators utilizing a variety of techniques. In terms of electrolyte wettability and adhesion of the coating materials, we provide an overview of the current status of research on coated separators, in situ modified separators, and grafting modified separators, and elaborate additional performance parameters of interest. The characteristics of inorganics coated separators, organic framework coated separators and inorganic–organic coated separators from different fabrication methods are compared. Future directions regarding new modified materials, manufacturing process, quantitative analysis of adhesion and so on are proposed toward next-generation advanced lithium batteries. Graphical abstract