fig7

Figure 7. (A) (i) and (ii) Schematic illustration of the synthesis process of the Se@PCNFs electrode; (iii) Photograph of free-standing and flexible Se@PCNFs electrode; (iv) Long-term cycling performance of Se@PCNFs electrode in Li-ion batteries at 0.5 A g^-1 for 900 cycles^[103]; Copyright 2015, Wiley-VCH. (B) (i) Digital photo of the flexible self-standing graphene-Se@CNT composite film; (ii) Charge/discharge profiles of the graphene-Se@CNT composite film with cycles at 0.1 C current rate; (iii) Cycling performance of the self-standing graphene-Se@CNT at 0.1 C^[104]; Copyright 2014, Elsevier. (C) (i) Schematic illustration of the synthesis process for Se@MCNF electrode; (ii) photograph of flexible and freestanding Se@MCNF electrode; (iii) Cyclic performances of the Se@MCNF electrode at a current density of 0.1 A g^-1 and coulombic efficiency during cycling^[105]; Copyright 2017, Wiley-VCH.