Unilamellar Metallic MoS2/Graphene Superlattice for Efficient Sodium Storage and Hydrogen Evolution

Unilamellar metallic nanosheets possess superiority for electrochemical energy storage and conversion applications compared to the few-layered bulk and semiconducting counterparts. Here, we report the utilization of unilamellar metallic 1T phase MoS2 nanosheets for efficient sodium storage and hydrogen evolution through a MoS2/graphene superlattice. The superlattice-like assembly composed of alternately restacked unilamellar MoS2 and modified reduced graphene oxide nanosheets was prepared by a facile solution-phase direct restacking method. As an anode for sodium storage, the MoS2/graphene superlattice anode exhibited an excellent rate capability of ∼240 mA h g–1 at 51.2 A g–1 and a stable reversible capacity of ∼380 mA h g–1 after 1000 cycles at 10 A g–1. In addition, a low onset potential of ∼88 mV and a small Tafel slope of 48.7 mV decade–1 were attained for the hydrogen evolution reaction. Our findings are important for further developing the potential of 2D nanosheets for energy storage and conversion.