Surface Redox-Active Organosulfur-Tethered Carbon Nanotubes for High Power and Long Cyclability of Na-Organosulfur Hybrid Energy Storage

Despite the clear benefits of Na and S active materials, Na-S hybrid energy storage devices have yet to be exploited, and existing Na-S batteries cannot provide fast kinetics and long-term stability. Herein, we describe chemical and electronic coupling of the redox-active organosulfur moiety (-S-S-S-) with carbon nanotube (CNT) networks for high power and long cyclability of Na-organosulfur hybrid energy storage devices. The facile and reversible surface redox kinetics of organosulfur-tethered CNT is associated with a two-electron transfer toward the formation of low-order polysulfide, as confirmed by in situ and ex situ analyses. The specific capacitance of SOS-OCNT is 377 F g-1 (94% of theoretical capacitance) and 61.3% of capacitance is retained at 10 A g-1. The Na-organosulfur hybrid full cells deliver an ultrahigh power density of 13.4 kW kg-1 and high energy density of 27 Wh kg-1 over 50000 cycles.