Metal–organic framework derived hierarchical porous TiO₂ nanopills as a super stable anode for Na-ion batteries

Hierarchical porous TiO₂ nanopills were synthesized using a titanium metal-organic framework MIL-125(Ti) as precursor. The as-synthesized TiO₂ nanopills owned a large specific surface area of 102 m²/g and unique porous structure. Furthermore, the obtained TiO₂ nanopills were applied as anode materials for Na-ion batteries for the first time. The as-synthesized TiO₂ nanopills achieved a high discharge capacity of 196.4 mAh/g at a current density of 0.1 A/g. A discharge capacity of 115.9 mAh/g was obtained at a high current density of 0.5 A/g and the capacity retention was remained as high as 90% even after 3000 cycles. The excellent electrochemical performance can be attributed to its unique hierarchical porous feature.