Reduced graphene oxide aerogel as stable host for dendrite-free sodium metal anode

Abstract

Sodium (Na) metal has attracted great attention as a promising anode for next-generation energy storage systems because of its abundant resources, potentially low cost, and high theoretical capacity. However, severe dendrite growth, large volume expansion during plating/stripping lead to poor cycle performance and limit the practical application of sodium metal anodes. Here, oriented freeze-drying and molten infusion are used to synthesize a Na-infused reduced graphene oxide aerogel (Na@rGa) composite anode using a reduced graphene oxide aerogel (rGa) as a stable host. This unique host shows ultra-light weight which guarantees high capacity (1064 mAh g−1), and the large specific surface area and uniform pores effectively lower the local current density and uniform electrolyte distribution from the inner to the outside of electrode. The Na@rGa anode exhibits low overpotential (50 mV) and stable cycle performance for 1000 cycles at 5 mA cm−2 in carbonate electrolyte system. The electrochemical performance of a full cell using the Na@rGa composite anode is clearly superior to that of a reference cell. This work provides a new horizon for construction of three-dimensional stable hosts and safe sodium metal anodes.