Na+/K+ hybrid battery based on a sulfurized polyacrylonitrile cathode

Abstract

Sulfurized polyacrylonitrile (SPAN) nanocomposites were synthesized and used as a cathode in a novel rechargeable Na+/K+ hybrid battery with high performance for the first time. When 0.9 mol NaPF6 and 0.1 mol KPF6 were dissolved in ethylene carbonate (EC)/dimethyl carbonate(DMC)/ethyl methyl cabonate(EMC) (4:3:2, v/v/v), used as hybrid electrolyte, Na foil was used as the anode, and SPAN composites were used as the cathode, a hybrid ion system was created via composition-decomposition between Na+/K+ and SPAN and stripping-depositing of Na+ with suppressed dendrites by taking advantage of the self-healing electrostatic shield effect. As a result, a highly reversible calculated capacity of 1405.5 mAh gsulfur-1 with a coulombic efficiency approaching 100% after 100 cycles was obtained at a current density of 35 mA g-1. This environmentally benign, low-cost Na+/K+ hybrid battery shows promise as a new future flexible energy storage system (ESS) technology.