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

Abstract 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 Zn 2+ adsorption and consequent Zn 2+ coordination with PBQS companied by de‐solvation process, as confirmed by in situ FT‐IR analysis. However, sluggish Zn 2+ de‐solvation leads to a loss of Zn 2+ 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 % H 2 O to the DMF electrolyte incorporates 0.24 H 2 O into the primary solvation sheath of Zn 2+ , significantly facilitating the de‐solvation process. As a result, the PBQS cathode (8 mg cm −2 ) retains its Zn 2+ 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.