Glycol Derived Carbon- TiO₂ as Low Cost and High Performance Anode Material for Sodium-Ion Batteries

Carbon coated TiO₂ (TiO₂@C) is fabricated by a convenient and green one-pot solvothermal method, in which ethylene glycol serve as both the reaction medium and carbon source without the addition of any other carbon additives. During the solvothermal process, ethylene glycol polymerize and coordinate with Ti⁴⁺ to form the polymeric ligand precursor, then the polymer brushes carbonize and convert to homogeneous carbon layer firmly anchored on the TiO₂ nanoparticles (~1 nm thickness). The polymerization and carbonization process of the ethylene glycol is confirmed by FT-IR, Raman, TG and TEM characterizations. Benefiting from the well-dispersed nanoparticles and uniform carbon coating, the as-prepared TiO₂@C demonstrate a high reversible capacity of 317 mAh g^-1 (94.6% of theoretical value), remarkable rate capability of 125 mAh g^-1 at 3.2 A g^-1 and superior cycling stability over 500 cycles, possibly being one of the highest capacities reported for TiO₂.