Durable GeP5-carbon anodes for sodium-ion batteries through elastomeric layer stabilization

Despite the abundance and low cost of sodium, the development of sodium-ion batteries (SIBs) is hindered by the lack of stable, high-capacity anodes. Here, we report an elastomeric polydopamine (PDA) coating as a multifunctional interfacial buffer layer for GeP 5 /C composites to enhance structural stability and electrochemical performance. The engineered GeP 5 /C-PDA electrode features a hierarchical core-shell architecture in which the PDA layer accommodates volume expansion, preserves interfacial integrity, and stabilizes the solid-electrolyte interphase during repeated cycling. Consequently, the GeP 5 /C-PDA electrode delivers a high initial discharge capacity of 1,023.7 mAh g −1 at 100 mA g −1 . It retains a capacity of 403.4 mAh g −1 after 200 cycles at 500 mA g −1 and exhibits excellent rate capability. This study demonstrates that integrating an elastomeric PDA layer with a conductive carbon network offers a scalable and effective strategy for developing high-performance alloy-type anodes for next-generation SIBs and practical applications.