High Na Mobility in rGO Wrapped High Aspect Ratio 1D SbSe Nano Structure Renders Better Electrochemical Na Battery Performance.

We chose to understand the cyclic instability and rate instability issues in the promising class of Na conversion and alloying anodes with Sb Se as a typical example. We employ a synthetic strategy that ensures efficient rGO (reduced graphene oxide) wrapping over Sb Se material. By utilization of the minimum weight of additive (5 wt.% of rGO), we achieved a commendable performance with a reversible capacity of 550 mAh g at a specific current of 100 mA g and an impressive rate performance with 100 % capacity retention after high current cycling involving a 2 Ag intermediate current step. The electrochemical galvanostatic intermittent titration technique (GITT) has been employed for the first time to draw a rationale between the enhanced performance and the increased mobility in the rGO wrapped composite (Sb Se -rGO) compared to bare Sb Se . GITT analysis reveals higher Na diffusion coefficients (approx. 30 fold higher) in the case of Sb Se -rGO as compared to bare Sb Se throughout the operating voltage window. For Sb Se -rGO the diffusion coefficients in the range of 8.0×10  cm  s to 2.2×10  cm  s were observed, while in case of bare Sb Se the diffusion coefficients in the range of 1.6×10  cm  s to 9.4×10  cm  s were observed.