Novel metallic titanium fluoride: A promising high capacity and superionic conductivity anode in Li-, Na-, and K-ion batteries

The transition metal fluorides have huge advantage as anode due to the small atomic mass of the F atom. But the formation of Li-F rings reduced the cycle life, and the open-framework structure induced the high diffusion barriers. We designed a non-open framework 1T-TiF2 structure. The remaining 3d electrons of Ti induced the 1T-TiF2 structure has good electronic conductivity, and large formation energy of 1T-TiF2 structure block the for-mation of Li-F rings. The 1T-TiF2 structure could serve as anode in Li-ion, Na-ion, and K-ion batteries with high stiffness, superionic conductivity and long cycle life. Our calculate results indicated that the 1T-TiF2 anode has competitive theoretical capacitance (208.08 mA h g- 1 for Li-ion battery, 277.45 mA h g- 1 for Na-ion battery, and 208.08 mA h g- 1 for K-ion battery). Furthermore, the good thermal, dynamic stability, oxidative corrosion resistance, and hydrophilicity confirmed the possibility of preparing 1T-TiF2 structure under laboratory condi-tions. Our study provides a reference for the light weighting of anodes.

Automated summary

Transition metal fluorides have advantages as anodes due to small atomic mass of F atom, but formation of Li-F rings and open-framework structure limit their cycle life and diffusion barriers. By designing a non-open framework 1T-TiF2 structure, competitive anode for Li-ion, Na-ion, and K-ion batteries with high stiffness, superionic conductivity, and long cycle life is achieved. The 1T-TiF2 anode has theoretical capacitance of 208.08 mA h g-1 for Li-ion, 277.45 mA h g-1 for Na-ion, and 208.08 mA h g-1 for K-ion batteries. Good thermal, dynamic stability, oxidative corrosion resistance, and hydrophilicity support the possibility of preparing 1T-TiF2 structure under laboratory conditions. This study provides reference for lightweight anodes.