Reconfiguration of hydrogen bond networks by thermal gelation to enhance interface stability for ultralong life zinc-ion batteries

The interface problems in zinc-ion batteries severely limit their electrochemical performance, even in hydrogel (HG) electrolyte (HE). Herein, a strategy of reconfiguring the hydrogen bond networks by thermal gelation is proposed to enhance the battery interface stability. The strategy introduces methyl cellulose into acrylamide, which can effectively stabilize the electrode interface and reconstruct the hydrogen bond networks of the electrolyte through its unique thermos-gelation property. Methylcellulose is dissolved by heating and cooled to form gel. This thermal gelation strategy formed hydrogen bonds with a large amount of free water and methyl cellulose, which not only reduced the water activity but also enhanced the intermolecular polymerization network and also promoted the solvation of Zn²⁺. More importantly, the symmetric batteries with HE-HG hydrogel electrolyte exhibited a long cycling life of 8000 h. The Zn||Zn_0.25V₂O₅ (Zn||ZVO) battery displays the low-capacity decay rate for 800 cycles at 1 C at −20 °C. The pouch battery maintains a capacity of 255 mAh·g⁻¹ after 100 cycles under 2.5 A·g⁻¹ at −20 °C. This study provides a new way to enhance the interfacial stability, which helps to realize the scale application of flexible zinc-ion batteries.