fig1

Figure 1. (A) Comparison of the basic properties of Li, Na, and K. (B) Schematic of the working principle of PIBs. (C) Illustration of the intercalation, conversion, and alloy types of PIB anodes. (D) Theoretical capacity and average voltage of various alloy anodes for PIBs. (E) Discharge-charge profiles and corresponding equilibrium potential (vs. K⁺/K) obtained according to ex-situ XRD results and discharge-charge profiles of porous-Sb. Reprinted with permission from Ref.^[23]. Copyright 2021, John Wiley and Sons. (F) Operando XRD analysis to investigate the structural evolution of the 2D-Bi anode for PIBs during the potassiation/depotassiation process. Reprinted with permission from Ref.^[24]. Copyright 2022, John Wiley and Sons.