fig5

Figure 5. PVA-based n-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. (A) Design schematic of PVA modified by sulfonate (-SO₃-). (B) Increase in -ΔV as a function of ΔT, representing the Seebeck coefficient. (C) Ionic conductivity (σ_i), thermal conductivity (κ), power factor (PF_i) and figure of merit (ZT_i) of hydrogel electrolytes. Reproduced with permission^[36]. Copyright 2025, Royal Society of Chemistry; (D) Schematic illustration of the fabricated i-TE materials based on coordination interaction between Na⁺ and -OH groups of NaOH-PVA hydrogels under the temperature gradient. Seebeck coefficient of fabricated PVA hydrogels (E) before and (F) after dry-annealing process with different NaOH concentrations. Reproduced under the terms of the Creative Commons CC-BY license^[29]. Copyright 2021, American Association for the Advancement of Science.