Graphene Oxide Confinement of Redox Species Enables Stable Li 2 SO 4 ‐Based Aqueous Batteries With Dual Soft‐Gel Electrodes

ABSTRACT Aqueous batteries are attractive for safe and low‐cost energy storage, yet their performance is fundamentally limited by uncontrolled migration of redox‐active species within electrode architectures. Here, we report a Li 2 SO 4 ‐based aqueous battery with dual soft‐gel electrodes enabled by sulfate‐induced phase separation, in which the polymer‐rich gel phases serve as redox‐host electrodes and the aqueous phase functions as the electrolyte. Although oxidized species are effectively immobilized, the dissolution and diffusion of reduced anthraquinone derivatives lead to rapid capacity decay. To address this challenge, graphene oxide (GO) is introduced into the anodic soft‐gel to regulate redox species transport. The high‐aspect‐ratio GO sheets, with micrometer‐scale lateral dimensions and nanoscale thickness, provide multiscale spatial confinement and possible interfacial interactions, while the initial electrochemical response is consistent with partial GO reduction during early cycling. Systematic tuning of the anthraquinone derivative (AQ)/GO ratio reveals a composition‐dependent balance between redox confinement and electrochemical polarization. These results demonstrate the effectiveness of GO‐assisted confinement in the present AQ‐based soft‐gel system and suggest a potential materials‐design approach for regulating mobile redox species in related soft‐matter electrochemical systems.