fig4

Figure 4. PVA-based p-type i-TE materials and their TE properties. The figure includes the structural representation of PVA and illustrates its interactions within the hydrogel network, highlighting the relationship between structure and TE performance such as ion transport and the Seebeck coefficient. (A) Structural illustration of a TE system enhanced by hydrogen ion interactions within a strong hydrogen bond system. (B) Diffusion coefficients of different ions in aqueous solution. (C) Seebeck coefficient of HCl, HNO₃, and H₂SO₄ in aqueous solution and PVA hydrogels. Reproduced with permission^[79]. Copyright 2022, American Chemical Society; (D) Schematic illustration of interatomic interactions between ions and PVA. (E) Increase in -ΔV as a function of ΔT, representing the Seebeck coefficient, and (F) Ionic conductivity as a function of NaBF₄ concentration. Reproduced with permission^[45]. Copyright 2023, Elsevier Ltd.