fig6

Figure 6. (A) Schematic of the mechanisms of K ion storage in CBC^[65]. Copyright 2019, Elsevier; (B) Schematic diagram for CPC^[74]. Copyright 2022, Elsevier; (C) Schematic illustration of the fabrication process of HDMC samples^[75]. Copyright 2022, Elsevier; (D) Schematic illustration of BO-CPs^[76]. Copyright 2021, Zhengzhou University; (E) Schematic diagram of N/O-3DC^[77]. Copyright 2021, Elsevier. CPC: Honeycomb porous hard carbon; HDMC: heteroatomic doping mushroom biomass carbon; BO-CPs: boron/oxygen heteroatom co-doped carbon particles; N/O-3DC: 3D N/O co-doped amorphous biomass-based carbon; CBC: bio-hard carbon.