Activating Organic Electrode for Zinc Batteries via Adjusting Solvation Structure of Zn Ions

Zinc‐organic batteries, combining the low cost and high capacity of Zn anodes with the tunable and sustainable properties of organic cathodes, have garnered significant attention. Herein, we present a zinc‐organic battery featuring a poly(benzoquinonyl sulfide) (PBQS) cathode, a Zn anode, and an N,N‐dimethylformamide (DMF)‐based electrolyte, which delivers a high capacity (200 mAh g‐1), excellent rate capability, and an ultra‐long cycle life (10,000 cycles) when tested with a low PBQS loading (2 mg cm‐2). The charge storage mechanism in the PBQS cathode involves solvated Zn2+ adsorption and consequent Zn2+ coordination with PBQS companied by de‐solvation process, as confirmed by in‐situ FT‐IR analysis. However, sluggish Zn2+ de‐solvation leads to a loss of Zn2+ coordination capacity when tested with higher PBQS loading (8 mg cm‐2) even at a low current density of 0.2 A g‐1. Remarkably, the addition of 2% H2O to the DMF electrolyte incorporates 0.24 H2O into the primary solvation sheath of Zn2+, significantly facilitating the de‐solvation process. As a result, the PBQS cathode (8 mg cm‐2) retains its Zn2+ storage capacity when using the modified electrolyte. This approach offers a new strategy for improving the rate performance of organic electrodes, complementing existing conductivity enhancements.