Improved Li‐Storage Performance of Li 4 Ti 5 O 12 Coated with CN Compounds Derived from Pyrolysis of Urea through a Low‐Temperature Approach

A uniform and thin amorphous layer of a CN compound was coated on porous Li 4 Ti 5 O 12 by pyrolysis of urea on its surface at a rather low temperature of 400 °C in an Ar atmosphere. Such a CN coating layer greatly improved the electrochemical performance of Li 4 Ti 5 O 12 . After coating, Li 4 Ti 5 O 12 showed good rate and excellent cycling performance. Reversible capacities for the coated sample of 134 and 105 mAh g −1 were obtained at current rates of 5C and 10C, respectively, in the voltage range of 1–2.2 V, which is approximately two and five times higher than those of pristine Li 4 Ti 5 O 12 at the same current rates. Excellent capacity retention of 95.8 % was achieved for the coated sample after 2000 cycles in a half cell at a 2C rate.