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Page 10 of 28 Choi et al. Energy Mater. 2025, 5, 500106 https://dx.doi.org/10.20517/energymater.2025.50

Table 1. TE performance of i-TE hydrogels with cellulose networks
Authors Polymers Ion conductors Type S [mV/K] σ [mS/cm] κ [W/mK]
i
i
i
Li et al. [30] Cellulose NaOH p 24 20 0.48
[35]
Qian et al. CMC LiCl p 2.96 36.51 0.575
PAM
[37]
Chen et al. CBC LiTFSI p 11.5 0.71 -
[40]
Han et al. PQ-10 NaOH p 24.2 0.3 -
Yang et al. [47] CMC NaCl p 17.1 26.8 -
PAA
Hu et al. [74] Cellulose BzMe NOH p 2.61 38 0.18
3
[76]
Cheng et al. Cellulose KCl P 22.1 0.64 0.31
Wu et al. [43] BC NaCl n -27.2 204.2 -
[50] 2-
Chen et al. Cellulose [CuCl ] n -26.3 8.47 0.47
4
PVA
[75]
Liu et al. Cellulose [BMIM][BF ] n -20.1 13.9 0.46
4
PAM
[77]
Chen et al. BC NaOH n -20.7 0.62 -
PVA
S : Ionic Seebeck coefficient; σ : ionic conductivity; κ : thermal conductivity; PQ-10: quaternized hydroxyethyl cellulose; CBC: carboxylated bacterial
i i i
cellulose; PAM: polyacrylamide; CMC: sodium carboxymethyl cellulose; BC: bacterial cellulose; PAA: polyacrylic acid; PVA: polyvinyl alcohol.

Figure 3. Cellulose-based i-TE materials and their TE properties. The figure includes the structural representation of cellulose and its role
in i-TE materials, highlighting key TE properties such as ion transport and Seebeck coefficient. (A) Schematic illustration of the enhanced
ion mobility and selectivity of the cellulosic membrane due to the nanochannels formed between the cellulose nanofibres and the effect
[30]
of intermolecular bonding. Reproduced with permission . Copyright 2019, Springer Nature; (B) Schematic diagrams of thermovoltage
generation in cellulose/BzMe NOH hydrogel. (C) Seebeck coefficient of cellulose/BzMe NOH hydrogel with various BzMe NOH
3 3 3
[74]
concentrations. Reproduced with permission . Copyright 2022, Elsevier Ltd; (D) Schematic illustration of ion thermal diffusion
2+
between nanofibers and molecular chains in Ca coordinated bacterial cellulose (CaBC) with NaCl hydrogel. (E) Ionic conductivities of
CaBC with different NaCl solution concentrations. (F) Ionic Seebeck coefficients of BC and CaBC hydrogels before and after soaking in
1 M NaCl solution. Reproduced with permission [43] . Copyright 2022, American Chemical Society.
diffusion, achieving a Seebeck coefficient of 38.20 mV K , twice that of conventional materials. Similarly,
-1
Hsiao et al. designed a double-network PVA/sodium alginate (SA)/polyethylene glycol (PEG) hydrogel,
incorporating NaBF to optimize Na transport while limiting BF mobility . The synergistic effects of
-
+
[45]
4
4
counter-ion condensation and PVA crystallinity resulted in a high Seebeck coefficient of 66.7 mV K and an
-1
ionic conductivity of 31.4 mS cm , along with a power factor of 13.96 mW m K [Figure 4D-F] . These
[45]
-1
-1
-2