fig4
![Two-dimensional nitrogen and phosphorus <InlineParagraph>co-doped</InlineParagraph> mesoporous carbon-graphene nanosheets anode for high-performance potassium-ion capacitor](https://image.oaes.cc/72c8916f-4ae0-44db-b7e7-c5092bb79ced/5602.fig.4.jpg)
Figure 4. Electrochemical performance, structural evolution, and surface information of N/P-MC@RGO anode during the K+ storage. (A) Cycling performance at a rate of 0.5 A g-1. (B) EIS spectra achieved after different cycles under a constant charging/discharging rate of 0.2 A g-1. (C) Ex situ Raman spectra, (D) C1s and K2p, (E) O1s XPS spectra for N/P-MC@RGO during the different charging/discharging stages. (F) TEM image, (G) ADF-STEM image, and the corresponding EDS mapping of (H) C-K, (I) O-K, and (J) K-K for N/P-MC@RGO after the long-term cycles.