A self-supported sodiophilic 3D Enteromorpha prolifera-derived carbon matrix enables dendrite-free sodium metal anodes
Sodium metal is considered an ideal anode material for high-performance sodium-based batteries. However, volume changes and dendrite growth during cycling seriously restrict its practical application. To address these challenges, this study utilizes harmful green tide algae Enteromorpha prolifera as a raw material to fabricate a self-supporting, sodiophilic, 3D Enteromorpha prolifera-derived carbon (EC) matrix via defect engineering. The results demonstrate that the 3D EC matrix can reduce nucleation overpotential, enhance binding ability with sodium atoms, and induce sodium to deposit horizontally inside EC, effectively addressing the issue of dendrite formation. Furthermore, the Na-EC symmetric cell demonstrates exceptional cycling stability with an ultralow polarization of 12 mV over 1000 h at 5 mA cm−2, 5 mA h cm−2. Notably, this stability persists even under ultrahigh current density and areal capacity conditions (30 mA cm−2, 30 mA h cm−2), maintaining stable operation for 500 h. When configured in full-cell systems with Na3V2(PO4)3 cathode, the assembled cell delivers an initial discharge capacity of 108.1 mA h g−1 at a 1 C rate, and maintains a capacity retention rate of 94.4% after 500 cycles. This study proposes an innovative strategy to advance high-performance dendrite-free sodium metal batteries through the recycling of marine environmental waste into functional energy materials.