Realizing an All‐Round Hydrogel Electrolyte toward Environmentally Adaptive Dendrite‐Free Aqueous Zn–MnO₂ Batteries

Abstract

Flexible energy storage devices are at the forefront of next‐generation power supplies, one of the most important components of which is the gel electrolyte. However, shortcomings exist, more or less, for all the currently developed hydrogel electrolytes. Herein, a facile and cost‐effective method is developed to construct an all‐round hydrogel electrolyte by using cotton as the raw material, tetraethyl orthosilicate as the crosslinker, and glycerol as the antifreezing agent. The obtained hydrogel electrolyte has high ionic conductivity, excellent mechanical properties (e.g., high tensile strength and elasticity), ultralow freezing point, good self‐healing ability, high adhesion, and good heat‐resistance ability. Remarkably, this hydrogel electrolyte can provide a record‐breaking high ionic conductivity of 19.4 mS cm−1 at −40 °C compared with previously reported aqueous electrolytes for zinc‐ion batteries. In addition, this hydrogel electrolyte can significantly inhibit zinc dendritic growth and parasitic side reactions from −40 to 60 °C. With this hydrogel electrolyte, a flexible quasi‐solid‐state Zn–MnO2 battery is assembled, which shows remarkable energy densities from −40 to 60 °C. The battery also exhibits outstanding cycling durability and has high endurance under various harsh conditions. This work opens new opportunities for the development of hydrogel electrolytes.

Immunizing Aqueous Zn Batteries against Dendrite Formation and Side Reactions at Various Temperatures via Electrolyte Additives

“…Furthermore, the constantly occurred side reactions on the Zn anode in aqueous electrolyte impede Zn 2+ transfer, reduce Zn/Zn 2+ reversibility, and exacerbate the Zn dendrite formation problem. [10,11] A lot of endeavor has been made to overcome the above issues, such as employing anti-freezing hydrogel electrolytes, [12][13][14][15] high concentrated "water in salt" electrolytes, [16] modifying the anode interface, [17] and adding electrolyte additives. [18][19][20][21] In these strategies, organic solvents as electrolyte additives have been certified to be low-cost and effective on the subzero temperature application and the dendrite inhibition of Zn-ion batteries.…”

Issues and rational design of aqueous electrolyte for Zn‐ion batteries

“…There have been a great number of researches on gel electrolyte with high ion conductivity and adhesion to hamper contact between aqueous solution and Zn anode. Recently, Chen and coworkers fabricated a versatile hydrogel electrolyte for dendrite‐free, noncorrosive, and long‐life AZIBs 66 . The as‐prepared CT3G30 hydrogel composed of cotton as the raw material of polymetric framework and tetraethyl orthosilicate as the crosslinker shows excellent adhesion with Zn electrodes and successfully limits free water molecules to induce side reaction.…”

A Universal Compensation Strategy to Anchor Polar Organic Molecules in Bilayered Hydrated Vanadates for Promoting Aqueous Zinc‐Ion Storage

“…[ 1–6 ] Recently, various cathode materials of aqueous Zn batteries have been developed such as Prussian blue analogs, manganese oxides, vanadium‐based compounds, and organic materials. [ 7–16 ] Among these cathode materials, vanadium‐based compounds have attracted great attention due to their open crystal structure and the abundant valence of vanadium. [ 17–20 ] Based on the V 5+ /V 3+ redox couple, V 2 O 5 possesses a superior theoretical capacity of 589 mAh g −1 in comparison with other vanadium‐based compounds.…”