Highly Stable Lithium/Sodium Metal Batteries with High Utilization Enabled by a Holey Two-Dimensional N-Doped TiNb<sub>2</sub>O<sub>7</sub> Host.

Huang, Zhongyi; Li, Zhen; Zhu, Ming; Wang, Guanyao; Yu, Fangfang; Wu, Minghong; Xu, Gang; Dou, Shi-Xue et al. · Nano Lett · 2021

basic_science · Level V

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Abstract

Lithium/sodium metal batteries have attracted enormous attention as promising candidates for high-energy storage devices. However, their practical applications are impeded by the growth of dendrites upon Li/Na plating. Here, we report that holey 2D N-doped TiNb<sub>2</sub>O<sub>7</sub> (N-TNO) nanosheets with high electroactive surface area and large amounts of lithiophilic/sodiophilic sites can effectively regulate Li/Na deposition as an interfacial layer, leading to an excellent cycling stability. The N-TNO interfacial layer enables the Li||Li symmetric cell to sustain stable electrodeposition over 1000 h as well as the Na||Na cell to stably cycle for 2400 h at 1 mA cm<sup>-2</sup> and 3 mA h cm<sup>-2</sup> with a depth of discharge as high as 50%. The full cells of the Li/Na anodes based on the N-TNO layer paired with the LiFePO<sub>4</sub> and NaTi<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> cathodes, respectively, show a very stable cycling over 1000 cycles at a negative-to-positive electrode capacity (N/P) ratio up to 3.