fig6

Figure 6. Electrochemical performances of as-prepared electrode for Li-S batteries: (A) Cycling performance of the PBF-S-50%, PBF@N-S-50%, and PBF@N@S-S-50% electrode over 200 cycles at 0.1C; (B) Rate capability of PBF@N@S-S-50%, PBF@N-S-50%, and PBF-S-50%; (C) CV profiles of PBF@N@S-S-50% electrode at the scan rate of 0.1 mV/s; (D) Galvanostatic charge-discharge curves of the PBF@N@S-S-50% at 0.1C. PBF: Bare biochar fibers; PBF@N: N-doped porous biochar fibers; PBF@N@S: N, S dual-doped porous biochar fibers.