fig17

Figure 17. (A) Rate and (B) cycling performance of NTO and NTO:Yb in a half cell. (C) Cycling performance of NTO:Ln and NTO (Ln = La, Er, Gd, Sm, Ce, Nd or Yb) at a current rate of 5 C with a cycle number of 1000 to 1500. Reproduced with permission from Ref.[224] (Copyright 2012, American Chemical Society). NTO: Na2Ti3O7.