Hydrogen‐Bond Disrupting Electrolytes for Fast and Stable Proton Batteries

Abstract

Rechargeable aqueous proton batteries are promising competitors for the next generation of energy storage systems with the fast diffusion kinetics and wide availability of protons. However, poor cycling stability is a big challenge for proton batteries due to the attachment of water molecules to the electrode surface in acid electrolytes. Here, a hydrogen‐bond disrupting electrolyte strategy to boost proton battery stability via simultaneously tuning the hydronium ion solvation sheath in the electrolyte and the electrode interface is reported. By mixing cryoprotectants such as glycerol with acids, hydrogen bonds involving water molecules are disrupted leading to a modified hydronium ion solvation sheaths and minimized water activity. Concomitantly, glycerol absorbs on the electrode surface and acts to protect the electrode surface from water. Fast and stable proton storage with high rate capability and long cycle life is thus achieved, even at temperatures as low as −50 °C. This electrolyte strategy may be universal and is likely to pave the way toward highly stable aqueous energy storage systems.

Design Strategies and Recent Advancements for Low‐Temperature Aqueous Rechargeable Energy Storage

“…Reproduced with permission. [ 90 ] Copyright 2022, Wiley‐VCH. g) The 1 H NMR results for the mixture of H 2 O and 2‐propanol under different temperature.…”

“…When sulfuric acid solutions were mixed with glycerol, rapid and stable proton storage under −50 °C can be simultaneously achieved without high‐concentration electrolyte (Figure 6f). [ 90 ] Obviously, ethanol and 2‐propanol have the tendency to localize water molecules. [ 91,96 ] 1 H NMR peak in the H 2 O/2‐propanol mixture gradually shifted downfield during temperature reduced, demonstrating the enhanced interaction between H 2 O and 2‐propanol (Figure 6g).…”

“…f) The long-term performance of the MoO 3 electrode cycled at 0.4 A g −1 under −50 °C. Reproduced with permission [90]. Copyright 2022, Wiley-VCH.…”

. Insights into the design of mildly acidic aqueous electrolytes for improved stability of Zn anode performance in zinc-ion batteries

“…principle that HER can be suppressed by disrupting the H-bond network of free water [25][26][27][28] . Figure 2B details the structure of the H-bond network of free water.…”

“…On the contrary, the molecules containing polar groups have a great affinity to water and exhibit hydrophilicity. Some polar organics, like alcohols [27,[40][41][42][43][44][45] , sulfones [39,46] , and nitriles [47][48][49] , are widely utilized as additives/cosolvents in Zn batteries. Their introduction can not only maintain the homogeneity of electrolytes but also restrict water activity by breaking the H-bond network of water.…”