Intermixed Cation–Anion Aqueous Battery Based on an Extremely Fast and Long‐Cycling Di‐Block Bipyridinium–Naphthalene Diimide Oligomer

Aqueous batteries, particularly those integrating organic active materials functioning in a neutral pH environment, stand out as highly promising contenders in the stationary electrochemical storage domain, owing to their unparalleled safety, sustainability, and low‐cost materials. Herein, a novel di‐block oligomer, serving as the negative electrode of an all‐organic aqueous battery, is shown to offer exceptional output capabilities. The battery's performance is further enhanced by a unique intermixed p/n‐type storage mechanism, which is able to simultaneously exchange light and naturally abundant Na+, Mg2+, and Cl−. Reaching up to 105 mAh g−1, this system shows remarkable capacity retention for several thousand cycles (6500 cycles, ≈40 days) in various neutral electrolytes, including raw ocean water (≈3000 cycles, ≈75 days). The surprisingly fast kinetics of this di‐block oligomer allow to attain an unmatched specific capacity of near to 60 mAh g−1electrode while entirely devoid of conducting additives, and more than 80 mAh g−1electrode with 10% carbon additive, as well as displaying an areal capacity as high as 3.4 mAh cm−2 at C rate. Full cell validation was demonstrated over 1600 cycles by virtue of a commercial 2,2,6,6‐tétraméthylpipéridin‐1‐yl)oxyl (TEMPO) molecule, which permitted an energy density of close to 40 Wh kg−1materials at C rate in a self‐pH‐buffered and inexpensive aqueous electrolyte. A novel di‐block oligomer of an all‐organic aqueous battery, is shown to offer exceptional output capabilities based on simultaneous exchange of abundant cations and anions. Reaching up to 105 mAh g‐1, it shows remarkable cyclability for thousands of cycles notably in raw seawater. Its surprisingly fast kinetics allows to attain 60 mAh g‐1electrode while entirely devoid of conducting additives.