Revealing the Reversible Anion Insertion/Deinsertion Mechanism of Organic Electrode

Organic electrodes hold considerable potential in terms of environmental sustainability and cost-effectiveness, and <i>p</i>-type electrodes, in particular, offer electrochemical performance on par with conventional inorganic-based systems. However, their electrochemical reaction mechanism has yet to be elucidated due to their unusual reaction nature of involving anion insertion. Herein, we propose, for the first time, the redox mechanism of <i>p</i>-type organic electrodes. The real-time observations on the reaction process capture that the <i>p</i>-type organic particles exhibit significant crystallographic and morphological transformation during the reaction. The discovery of the solvated intermediate state during the reaction process reveals that this anomalous reaction behavior occurs via solution-mediated reactions, which results from the flattening of the molecular structure upon oxidation. In addition, the <i>p</i>-type organic electrode exhibited a remarkable rate capability and cycle stability that can only be explained by solution-mediated reactions, defying previous misconception on organic electrodes based on conventional solid-ion transport process. This study provides insights into the fundamental operating mechanism of <i>p</i>-type organic batteries, thus paving the way for the strategic development of high-performance systems.