Fluorine enhanced nucleophilicity of TiO2 nanorod arrays: A general approach for dendrite-free anodes towards high-performance metal batteries

The effective depress dendrite growth of metal anodes (such as lithium (Li), sodium (Na), potassium (K) and zinc (Zn)) have been widely considered for metal-based batteries. However, regarding varied metal batteries accompanied with different chemical environment (e.g, solvent effect, electronegativity and ion radius), it is a huge challenge to develop a general approach for construction of dendrite-free metal anodes. Herein, we report a strategy to induce Li, Na, K and Zn homogenous nucleation by ‘F’ heteroatom doped TiO2 nanorod arrays. Theoretical calculations reveal that Li+, Zn2+, Na+ and K+ can be strong adhered to electronegative F heteroatom, giving rise to an enhanced nucleophilicity. Consequently, the CC/TiO2-F based Li, Zn, Na and K symmetric cells exhibit remarkably enhanced long service life of 1100 h, 530 h, 720 h and 510 h at 2 mA cm–2 with a low voltage hysteresis, which is 4.4, 26.5, 24.1 and 25.5 times higher than that of bare CC based anodes. Moreover, the CC/TiO2-F dendrite-free anode allows for construction of Li-LiFePO4/Sulfur full-batteries with a high capacity of 152 mA h g–1 and 1070 mA h g–1, respectively. Additionally, the assembled Li–S pouch cells also realized high stable capacity with high flexibility. This work provides an important strategy to develop general method for dendrite-free metal anodes towards high-performance metal batteries.