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 situtransmission 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 situstudy 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. 160A2160 (2013)
2. S. P. Ong, V. L. Chevrier, G. Hautier, A. Jain, C. Moore, S. Kim, X. Ma, G. Ceder,
Energy Environ. Sci. 43680 (2011)