fig2

Figure 2. Schematic diagram of fundamental characteristics and functional mechanisms of heterostructures in rechargeable batteries. Hierarchical architectures^[24], under CC BY 4.0 license; Defect and strain^[25], reprinted with permission, Copyright © 2025 Wiley; Redox mediation^[26], reprinted with permission, Copyright © 2025 Wiley; Built-in fields^[27], under CC BY 4.0 license. HER: Hydrogen evolution reaction; UOR: urea oxidation reaction.