The lyotropic liquid crystalline (LLC) mesophase forms upon evaporation of water from aqueous solutions of LiX salts (X is Cl − , Br − , NO 3 − , or SCN − ) and a surfactant [C 12 H 25 (OCH 2 CH 2 ) 10 OH, abbreviated as C 12 E 10 ]. The LiX/ C 12 E 10 /H 2 O aqueous solutions have been monitored (during evaporation of their excess water to obtain stable LLC mesophases) by gravimetric, spectroscopic, and conductivity measurements to elucidate the role of water in these mesophases. The water/salt molar ratio in stable mesophases changes from 1.5 to 8.0, depending on the counteranion of the salt and the ambient humidity of the laboratory. The LiX/C 12 E 10 /H 2 O LLC mesophases lose water at lower humidity levels and absorb water at higher humidity levels. The LiCl-containing mesophase holds as few as four structural water molecules per LiCl, whereas the LiNO 3 mesophase holds 1.5 waters per salt (least among those assessed). This ratio strongly depends on the atmospheric humidity level; the water/LiX mole ratio increases by 0.08 ± 0.01 H 2 O in the LLC mesophases per percent humidity unit. Surprisingly, the LLC mesophases are stable (no salt leaching) in broad humidity (10−85%) and salt/surfactant mole ratio (2−10 LiX/C 12 E 10 ) ranges. Attenuated total reflectance Fourier transform infrared spectroscopic data show that the water molecules in the mesophase interact with salt species more strongly in the LiCl mesophase and more weakly in the case of the nitrate ion, which is evident by the shift of the O−H stretching band of water. The O−H stretching peak position in the mesophases decreases in the order ν LiCl > ν LiBr > ν LiSCN > ν LiNO 3 and accords well with the H 2 O/LiX mole ratio. The conductivity of the LLC mesophase also responds to the amount of water as well as the nature of the counteranion (X − ). The conductivity decreases in the order σ LiCl > σ LiBr > σ LiNO 3 > σ LiSCN at low salt mole ratios and in the order σ LiBr > σ LiCl > σ LiNO 3 > σ LiSCN at higher ratios due to structural changes in the mesophase.

By replacing volatile and flammable organic-based electrolytes with gel electrolytes, dye-sensitized solar cells (DSSCs) may be a viable and more practical alternative to other clean energy sources. Although they present a promising alternative, gel electrolytes still have some drawbacks for practical applications, such as low ionic conductivity and infusion difficulties into the pores of the working electrode. Here, we introduce a new one-step fabrication method that uses a lyotropic liquid crystalline (LLC) gel electrolyte (LiI:I 2 :H 2 O:C 12 H 25 (OCH 2 CH 2 ) 10 OH) and a dye (N719) to construct a DSSC that performs (7.32%) 2.2 times better compared with a traditional two-step production. Water plays a key role in the gel electrolyte, where the H 2 O/LiI mole ratio is around 2.57 under ambient laboratory conditions (ALCs); however, this ratio linearly increases to 4.00 and then to 5.85 at 40 and 75% humidities, respectively, without affecting the two-dimensional (2D) hexagonal structure of the mesophase. The ionic conductivity of the gel electrolyte linearly increases accordingly, by 2.2 (4.8 × 10 −5 to 10.6 × 10 −5 ) and 13.1 times (63.0 × 10 −5 S/ cm) from ALC to 40 and ALC to 75% humidity, respectively. Increasing water in the gel phase improves the conductivity of the LLC mesophase and the short-circuit current (I sc ) of the DSSC, but negatively influences the open-circuit voltage (V oc ) of the cell, equilibrium reaction between the LiI and I 2 , and the anchoring of the dye molecules over the titania surface.

The molten phase of transition metal and lithium salts self‐assemble with non‐ionic surfactants to form lyotropic liquid crystalline (LLC) mesophases, which are important in the development of gel‐electrolytes and mesoporous materials. Here, we show that LiH2PO4 forms a semi‐stable LLC mesophase with 10‐lauryl ether (C12H25(OCH2CH2)10OH, C12E10), decoded as Li−EO−X (X is LiH2PO4/C12E10 mole ratio and between 2 and 200). The stability of the Li−EO−X phase is improved by increasing salt concentration (X>20) in the media. The semi‐stable Li−EO−X mesophase is further stabilized by adding either water by controlling the humidity or H3PO4 (PA) to the media. The phase behaviour of the above samples was investigated using POM, XRD, conductivity, and ATR‐FTIR measurements. The addition of PA not only brings stability and higher conductivity (increase from 0.1 to 8.9 mS/cm) to the mesophase but also produce an LLC gel‐electrolyte with a high buffer capacity that may be useful and important in various applications.