Achieving stable Na metal cycling via polydopamine/multilayer graphene coating of a polypropylene separator

Abstract Sodium metal batteries are considered one of the most promising low-cost high-energy-density electrochemical energy storage systems. However, growth unfavourable Na deposition and limited cell cycle life hamper application this battery system at a large scale. Here, we propose use polypropylene separator coated with composite material comprising polydopamine multilayer graphene to tackle these issues. The oxygen- nitrogen- containing moieties as well nano- meso- porous network coating allow cycling electrodes in symmetric configuration for over 2000 h stable 4 mV overpotential 1 mA cm ?2 . When tested full || 3 V 2 (PO ) coin cell, enables delivery capacity about 100 mAh g ?1 500 cycles (90% retention) specific current 235 satisfactory rate capability performances (i.e., 75 3.5 A ).