Figure 4

(a) Specific discharge capacity and coulombic efficiency of SnO2@C@half-rGO (red), SnO2@C/rGO (blue) and SnO2/C (grey) at 100 mA g−1. (b) Specific charge and discharge capacity of SnO2@C@half-rGO (red) and SnO2@C/rGO (blue) at 1 A g−1. (c) Mechanism of the structure evolution of SnO2@C@half-rGO and SnO2@C/rGO during lithiation/delithiation.