Fig. 3. Electrochemical characterization of SF@G upon cycling.

a Charge–discharge profiles of SF@G, SF@G-HF, and SF at 0.2 A g⁻¹ for the first cycle. b Coulombic efficiency of SF@G, SF@G-HF, and SF for initial five cycles. c Cycling performance of the SF@G and control electrodes over 500 cycles at 0.2 A g⁻¹ for initial two cycles and 2 A g⁻¹ for subsequent cycles. The Coulombic efficiency of SF@G is plotted on the secondary y-axis. d Reversible capacity and Coulombic efficiency vs. cycle plots of the LFP//SF@G full cell with SF@G as the anode and a commercial lithium iron phosphate (LFP) as the cathode (it is noteworthy that the capacity is based on the weight of active materials in the cathode).