fig3

Figure 3. (A) Diagram illustrating the several stages of K-intercalated graphite, with K represented in blue and C shown in yellow. (B) The charge-discharge curves of K⁺ and Li⁺ embedded in graphite at ambient temperature and pressure, respectively. (C) Potential distribution of K⁺ embedded in graphite at different stages based on DFT calculation. The interlayer stage is represented by the blue line [Theory (a)]: Stage-III (KC₂₄) → Stage-II (KC₁₆) → Stage-I (KC₈). The dotted green line [Theory (b)] represents the computed value of the phase that was previously reported: Stage-II (KC₂₄) → Stage- I (KC₈). The red dotted line is used to correct the capacitance contribution formed by SEI. Copyright 2015, Nano Letters^[29]. (D) Schematic diagram of the potassium/dipotassium process in the GDY layer. Copyright 2022, ACS Nano^[30]. (E) Schematic illustration of the preparation process for MG. Copyright 2021, Carbon^[31].