Revealing the dissolution mechanism of organic carbonyl electrodes in lithium−organic batteries

Abstract

Organic carbonyl electrode materials (OCEMs) have shown great promise for high-performance lithium batteries due to the high capacity, renewability, and environmental friendliness. Nevertheless, the severe dissolution of these materials in conventional electrolytes results in poor cycling stability, which hinders their practical application. Herein, a unified model considering the effects of both ion-solvation structures and electrolyte solvents is proposed to elucidate the dissolution mechanism of OCEMs in electrolytes. In this new model, the dissolution is driven by the interactions of OCEMs with ion-solvation structures and free (uncoordinated) solvents in electrolytes. In non-polar electrolytes, the strong interactions between OCEMs and Li-anion aggregates accelerate the dissolution of OCEMs, leading to anomalously high solubility of OCEMs. Conversely, the high dissolution in strongly polar electrolytes is dominated by the interaction with free solvents. This unified model transcends the conventional perspective that dissociation solely depends on the solutes-solvents interactions. Based on this model, we propose that tuning the effects of ion-solvation structures and free solvents by altering solvent polarity could be an effective strategy for inhibiting the dissolution of organic electrodes to achieve long-cycle Li−organic batteries.