fig19

Figure 19. (A) Schematic of the structure and mechanism of the heat conduction effect enhanced hydrovoltaic power generator (HCEHG) for sustained evaporation electricity output and thermoelectric conversation. (B) V_oc the hydrovoltaic module with and without the thermoelectric module. (C) Real-time temperature plots of the surfaces of the dual-size Al₂O₃ hydrovoltaic module and thermogalvanic module and corresponding temperature difference. The ambient temperature is ~290.4 K. Grey areas indicate that the device is illuminated. (D) Voltage profile of the device with the fully developed oxidation layer under 50% RH as a function of time when the temperature difference was altered. The inset shows the saturated voltage at the corresponding temperature to seek the slope (93 mV K^-1). Note it has the opposite sign (-93 mV K^-1) based on Equation 1 in this work. (E₁-E₄) Illustration showing thermoelectric voltage generation and the corresponding potential changes in the hotter and colder sides. Top left: Uniformly distributed water in PANI:PSS under ΔT = 0. Top right: As ΔT > 0, water molecules migrated from the hotter to the colder side. Bottom right: Voltage generation at steady state under ΔT > 0. Bottom left: Water molecules returned to their initial distributed states under ΔT approaching 0. (F) Evans diagram shows the cathodic-reduction reaction (black line), and the anodic oxidation reaction (greenish line) under uniform temperature. The greenish line shifts toward the red (or blue) line with less (or more) water on the electrodes. (A-C) Reprint with permission Ref.^[11]. Copyright 2022, The Author(s), Springer Nature. (D-F) Reprint with permission Ref.^[104]. Copyright 2021, The Author(s), Springer Nature.