Modulating electrolyte structure for ultralow temperature aqueous zinc batteries

Abstract

Rechargeable aqueous batteries are an up-and-coming system for potential large-scale energy storage due to their high safety and low cost. However, the freeze of aqueous electrolyte limits the low-temperature operation of such batteries. Here, we report the breakage of original hydrogen-bond network in ZnCl2 solution by modulating electrolyte structure, and thus suppressing the freeze of water and depressing the solid-liquid transition temperature of the aqueous electrolyte from 0 to –114 °C. This ZnCl2-based low-temperature electrolyte renders polyaniline||Zn batteries available to operate in an ultra-wide temperature range from –90 to +60 °C, which covers the earth surface temperature in record. Such polyaniline||Zn batteries are robust at –70 °C (84.9 mA h g−1) and stable during over 2000 cycles with ~100% capacity retention. This work significantly provides an effective strategy to propel low-temperature aqueous batteries via tuning the electrolyte structure and widens the application range of temperature adaptation of aqueous batteries.

Boosting Zinc Electrode Reversibility in Aqueous Electrolytes by Using Low‐Cost Antisolvents

“…This value is relatively similar to that for ZnSO 4 powder of ≈1092.4 cm −1 and therefore confirms the modified Zn 2+ solvation sheath. The weakened Zn 2+ solvation affects the transference number ( t ) in the electrolyte of Anti‐M‐50 % [26] . As shown in Figure S5, t was computed to be 0.48, higher than that for aqueous ZnSO 4 electrolyte (0.34), [5, 7a] which suggests a faster migration speed of Zn 2+ in Anti‐M‐50 %.…”

Zinc Metal Energy Storage Devices under Extreme Conditions of Low Temperatures

“…Chen et al. reported the breakage of hydrogen bonding networks in concentrated ZnCl 2 electrolytes (Figure 2d) [57] . As shown in Figure 2e, the freezing point can be decreased to −114 °C by modulating the concentration of electrolytes.…”

“…Chen et al reported the breakage of hydrogen bonding networks in concentrated ZnCl 2 electrolytes ( Figure 2d). [57] As shown in Figure 2e, the freezing point can be decreased to À 114°C by modulating the concentration of electrolytes. The Zn-polyaniline (PANI) battery using this electrolyte can work at a wide temperature range from -90 to 60°C, better than the common electrolytes (Figure 2fÀ h).…”

“…[93] Recently, Chen et al reported a PANI cathode for Zn batteries. [57] It was demonstrated that by combining with an anti-freezing electrolyte, the ZnÀ PANI battery can be stably cycled at À 70°C. Besides, a high capacity retention of 64.7 % was achieved even at À 50°C.…”

“…h) The comparison of different electrolytes at low temperatures. Reproduced from Ref [57]. with permission.…”