In Situ Electrochemical Reactions of Zn4Sb3 Nanowires with Li and Na: Fast Sodiation Rate and Excellent De/Sodiation Cyclablility

Besides its abundance and low cost, Na-ion is also in procession of weak Lewis acidity and large polarizability, which allow fast charge transfer reaction at electrode/electrolyte interface and in bulk diffusion.^1,2 These advantages make Na-ion battery an attractive and potential alternative to the well established Li-ion battery.  However, the development of Na-ion battery is currently a challenge due to lack of suitable active materials for both cathodes and anodes.

Here, an in-depth comparative study between the electrochemical de/lithiation and de/sodiation of Zn₄Sb₃ nanowires has been conducted by using in situ transmission electron microscopy. Surprisingly, we found that the sodiation rate of Zn₄Sb₃ nanowires is almost 10 times higher than their lithiation rate under similar testing conditions. In addition, the cracks were often observed in the first few cycles during de/lithiation of the Zn₄Sb₃ nanowire. However, there was no crack formed even after 20 cycles during their de/sodiation. Our in situ study indicates that the Zn₄Sb₃ nanowires exhibit better rate capability and cyclablility in Na-ion battery compared to Li-ion systems. The underlying reason has also been deeply investigated from the thermodynamic and kinetic aspects of ions transport in Zn-Sb intermetallics.

1. M. Okoshi, Y. Yamada, A. Yamada, H. Nakai, J. Electrochem. Soc.160 A2160 (2013)

2. S. P. Ong, V. L. Chevrier, G. Hautier, A. Jain, C. Moore, S. Kim, X. Ma, G. Ceder, Energy Environ. Sci. 4 3680 (2011)