A Postspinel Anode Enabling Sodium-Ion Ultralong Cycling and Superfast Transport via 1D Channels

5 years ago

A Postspinel Anode Enabling Sodium-Ion Ultralong Cycling and Superfast Transport via 1D Channels

Qi Li, Ping He, Kezhu Jiang, Haoshen Zhou, Shaohua Guo, Kai Zhu, Xiaoyu Zhang

Sodium-ion batteries are intensively investigated for large-scale energy storage due to the favorable sodium availability. However, the anode materials have encountered numerous problems, such as insufficient cycling performance, dissatisfactory capacity, and low safety. Here, a novel post-spinel anode material, i.e., single-crystalline NaVSnO4, is presented with the confined 1D channels and the shortest diffusion path. This material delivers an ultra long cycling life (84% capacity retention after 10 000 cycles), a high discharging capacity (163 mA h g−1), and a safe average potential of 0.84 V. Results indicate that the post-spinel structure is well maintained over 10 000 cycles, surprisingly, with 0.9% volume change, the Sn4+/Sn2+ based redox enables two sodium ions for reversible release and uptake, and the diffusion coefficient of sodium ions is characterized by 1.26 × 10−11 cm2 s−1. The findings of this study provide a new insight into design of new frameworks with polyelectronic transfers for full performance electrode materials of sodium-ion batteries. A novel post-spinel NaVSnO4 as the anode material is first developed for sodium-ion battery. The prepared NaVSnO4 electrode exhibits an ultra long cycling life of 84% capacity retention after 10 000 cycles, a remarkable diffusion coefficient of sodium ions of 1.26 × 10−11 cm2 s−1, and a high reversible capacity of 163 mA h g−1 based on the double charge transfers of Sn4+/Sn2+.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/aenm.201700361