Fig. 4: Electrochemical impedance properties comparison.

Nyquist plots of a HAN@SnO₂//HAN@SnO₂, b HAN@SnO₂@MnO₂//HAN@SnO₂@MnO₂, and c HAN@SnO₂@PPy//HAN@SnO₂@PPy MSCs with different pore depths of HAN. d Comparison of the charge transport resistance (R_ct) of different HAN-based MSCs.