Integration of deformable matrix and lithiophilic sites for stable and stretchable lithium metal batteries

In response to the growing interest in wearable devices, the demand for next-generation wearable devices that can endure various mechanical deformations such as folding and stretching is also increasing. As a result, the development of stretchable batteries, capable of operating under diverse conditions, is regarded as crucial for the advancement of these future wearable technologies. Many current studies on stretchable batteries suffer from limited energy density and complicated fabrication procedures. Thus, the development of batteries that meet both high stretchability and energy density remains challenging due to these factors. Herein, we propose a stretchable and lithiophilic matrix as a host for lithium (Li) metal anodes to realize stretchable Li metal batteries (LMBs), which consists of a polymer matrix embedded with silver nanoparticles (AgNPs). The lithiophilic AgNPs are incorporated both on the surface and within the elastic fiber matrix, providing facile Li nucleation kinetics and an electron-conductive network. Surface AgNPs serve as a primary electron pathway and offer numerous nucleation seeds to facilitate uniform Li electrodeposition. Meanwhile, AgNPs embedded in the matrix provide a sturdy conductive network even under mechanical deformation. Consequently, the structure-forming factors of stretchable lithiophilic Ag-incorporated matrix (SLiM) electrode contribute to enhanced electrochemical properties as a versatile Li metal host. As a proof of concept, the designed all-stretchable LMB with the SLiM electrode demonstrates minimal degradation of electrochemical performance in deformable conditions and confirms the feasibility of an LMB in stretchable application. This work provides insight into stretchable LMBs aimed at both highly deformable and high-energy-density wearable devices.