Nacre-inspired hybrid interface enabling controlled lithium deposition via ion modulation for lithium–sulfur batteries

The performance of the lithium-metal anode is a key factor influencing the cycling stability of lithium–sulfur (Li–S) batteries. Here, we present a nacre-inspired hybrid protective layer (PBN-Li), composed of polyethylene oxide (PEO) and boron nitride nanosheets (BNNSs), applied to Li-metal anodes. The alternating soft–rigid layered architecture, mimicking natural nacre, enables a synergistic balance between mechanical robustness and interfacial adaptability. This structure not only enhances interfacial stability and capacity retention, but also contributes to lithium ion modulation, promoting uniform Li deposition and preventing dendrite formation. The well-dispersed hybrid components effectively suppress Li-metal depletion and electrolyte degradation. In addition, the high Li+ conductivity of both PEO and BNNS ensures sufficient ionic transport across the interface. As a result, the symmetric PBN-Li cell delivers remarkable cycling stability for over 400 h at 1 mA/cm2 and excellent rate performance up to 5 mA/cm2. Real-time observations further reveal the role of the hybrid protective layer in stabilizing lithium metal and enhancing long-term battery operation. A full cell paired with a sulfur cathode also demonstrates high-rate capability and outstanding cycle life, highlighting the effectiveness of the ion-regulating, nacre-inspired interface for advanced Li–S battery systems.