J.Q. Qin, H.D. Shi, K. Huang, P.F. Lu, P.C. Wen, F.F. Xing, B. Yang, M. Ye*, Y. Yu* and Z.-S. Wu*
Nature Communications, 2021, 12, 5786.
DOI: 10.1038/s41467-021-26032-1 [PDF]
Sodium metal batteries are considered one of the most promising low-cost high-energy-density electrochemical energy storage systems. However, the growth of unfavourable Na metal deposition and the limited cell cycle life hamper the application of this battery system at a large scale. Here, we propose the use of polypropylene separator coated with a composite material comprising polydopamine and multilayer graphene to tackle these issues. The oxygen- and nitrogen- containing moietiesas well as the nano- and meso- porous network of the coating allow cycling of Na metal electrodesin symmetric cell configuration for over 2000 hours with a stable 4 mV overpotential at 1 mA cm-2. When tested in full Na || Na3V2(PO4)3coin cell, the coated separator enables the delivery of a stable capacity of about 100 mAh g-1for 500 cycles (90% capacity retention) at a specific current of 235 mA g-1and satisfactory rate capability performances (i.e., 75 mAh g-1at 3.5 A g-1).