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Abstract Aqueous all‐polymer proton batteries (APPBs) consisting of redox‐active polymer electrodes are considered safe and clean renewable energy storage sources. However, there remain formidable challenges for APPBs to withstand a high current rate while maximizing high cell output voltage within a narrow electrochemical window of aqueous electrolytes. Here, a capacitive‐type polymer cathode material is designed by grafting poly(3,4‐ethylenedioxythiophene) (PEDOT) with bioinspired redox‐active catechol pendants, which delivers high redox potential (0.60 V vs Ag/AgCl) and remarkable rate capability. The pseudocapacitive‑dominated proton storage mechanism illustrated by the density functional theory (DFT) calculation and electrochemical kinetics analysis is favorable for delivering fast charge/discharge rates. Coupled with a diffusion‐type anthraquinone‐based polymer anode, the APPB offers a high cell voltage of 0.72 V, outstanding rate capability (64.8% capacity retention from 0.5 to 25 A g−1), and cycling stability (80% capacity retention over 1000 cycles at 2 A g−1), which is superior to the state‐of‐the‐art all‐organic proton batteries. This strategy and insight provided by DFT and ex situ characterizations offer a new perspective on the delicate design of polymer electrode patterns for high‐performance APPBs.