notorious Zn dendrites and hazardous side reactions ascribing to the interactions between Zn 2+ and the functional groups in hydrogel. [8][9][10][11][12][13][14] Nevertheless, battery electrolytes with conventional hydrogels will be ineluctably freezing at subzero temperatures due to the relatively high freezing point of water. This can dramatically deteriorate the polymer gel mechanical property and ionic conductivities, [15,16] resulting in inferior cycling stability or even occurring short circuit. [17] In addition, the mechanical property of the hydrogel electrolyte should also be elaborately designed, to simultaneously satisfy the flexibility of wearable batteries and withstand the acting force during daily operation.Generally, hydrogel freezing is mainly on account of the strong HB formation between water molecules on polymer chains. [18,19] To date, two main strategies including the organic additives [20][21][22][23][24][25] and high concentration salts [26][27][28][29][30] are demonstrated on breaking the HB of water to achieve batteries with low temperature performance. The organic additives can form new HB with water molecules for achieving ultralow freezing point, and regulate the Zn 2+ solvation structure by coordinating with Zn 2+ for dendrite and side reaction suppression. [20,21,23] However, the radii of the Zn 2+ solvation structure are increased during the coordination, which significantly decrease the ionic conductivity of the batteries especially at subzero temperatures. [31] For high-concentration salts, they own much higher ionic conductivity than organic molecules, [26][27][28][29]32] but are expensive and undergo poor electrolyte wettability and severe salt precipitation at low temperature. [33][34][35] Critically, the mechanical durability of the hydrogel will be deteriorated by the high concentration salts when cooperated in batteries. Apart from the abovementioned strategies, grafting alcohol molecules to the polymer chains can also dedicate to the hydrogel antifreezing, whereas the fabrication process is tedious and complicated comparatively. [36,37] Therefore, exploring a new salt with low concentration to confer the hydrogel electrolyte with adjustable mechanical property and high ionic conductivities at subzero temperatures is of great importance.The Hofmeister effect is one of the ubiquitous phenomenon in nature, including two distinct solvation behaviors for hydrogels regarded as the "salting out" effect of the kosmotropes and "salting in" effect of the chaotropes. [38][39][40][41][42] Current literatures have employed inorganic salts to tailor the mechanical property The new-generation flexible aqueous zinc-ion batteries require enhanced mechanical properties and ionic conductivities at low temperature for practical applications. This fundamentally means that it is desired that the hydrogel electrolyte possesses antifreezing merits to resist flexibility loss and performance decrease at subzero temperatures. Herein, a highly flexible polysaccharide hydrogel is realized in situ and ...