Surface-redox sodium-ion storage in anatase titanium oxide

• DOI: 10.1038/s41467-022-35617-3
• Publication Date: 2023-01-03T10:03:09Z
• Authors: Qiulong Wei; Xiaoqing Chang; Danielle Butts; Ryan DeBlock; Kun Lan; Junbin Li; Dongliang Chao; Dong-Liang Peng; Bruce Dunn
• Keywords: Science; Q; 600; 02 engineering and technology; 0210 nano-technology; 7. Clean energy; Article

Sodium-ion storage technologies are promising candidates for large-scale grid systems due to the abundance and low cost of sodium. However, compared well-understood lithium-ion mechanisms, sodium-ion remains relatively unexplored. Herein, we systematically determine properties anatase titanium dioxide (TiO2(A)). During initial sodiation process, a thin surface layer (~3 5 nm) crystalline TiO2(A) becomes amorphous but still undergoes Ti4+/Ti3+ redox reactions. A model explaining role dependence specific capacity on size nanoparticles is proposed. Amorphous ~10 nm seem be optimum in terms achieving high capacity, order 200 mAh g-1, at charge/discharge rates. Kinetic studies indicate that surface-redox mechanism not dependent nanoparticle contrast lithiation which diffusion-limited intercalation process. The result excellent rate capability, cycling stability overpotentials. Moreover, tailoring enables thick electrodes retain properties, represents direction high-power storage.