Abstract: To address the cycling stability of zinc-ion batteries resulting from zinc dendrites, this work proposes the utilization of sulfonic groups to modulate the de-solvation and adsorption energy of zinc ions, achieving the horizontal growth of zinc dendrites. Using polyacrylamide (PAM) and carboxymethyl cellulose (CMC) composite gels as modification targets, sodium dodecyl sulfate (SDS) provides the sulfonic group, the PAM/CMC/SDS gel electrolyte exhibits a coordination number as low as 0.19 and a desolvation energy reaching up to 2.73 eV. Based on this, the gel electrolyte exhibits a wide operating voltage range of 2.93 V, effectively suppressing both hydrogen and oxygen evolution reactions. More importantly, zinc ions in the PAM/CMC/SDS electrolytes preferentially grow along the zinc (002) plane, characterized by higher adsorption energy, leading to the formation of a uniform and dense zinc deposit, rather than vertical growth on the (100) crystal plane. The successfully induced directional deposition of zinc crystals and mitigation of hydrogen evolution enables the PAM/CMC/SDS gel electrolyte to achieve remarkable cycling stability in Zn||Zn symmetrical cells for up to 2800 h, In addition, the Zn||MnO₂ asymmetric battery exhibits a specific capacity of 334 mAh g^-1, accompanied by excellent rate performance, which ensures the reliability and durability of the quasi-solid-state zinc-ion battery based on the gel electrolyte in dynamic practical applications.

Key words: Self-healing gel, Sulfonic acid modification, PAM/CMC gel, Adsorption energy, Zinc dendrite inhibition