Fig. 3. Bi2O3@C electrode: (a) CV curves at different scan rates; (b) GCD curves at different current densities; (c) the corresponding specific capacities calculated by GCD curves; (d) cycle performance for 4000 cycles at 5 A g−1. (e) The separation of the capacitive and diffusion-controlled discharge contributions. (f) Nyquist plots and the equivalent circuit for the EIS fittings.
