Functional Group-Driven Dissolution and Interfacial Instability in Naphthalene-Derived Organic Anodes for Li-Ion Storage

The practical viability of small-molecule organic anodes is often limited by active material dissolution and the accompanying interfacial instability in liquid electrolytes. Herein, we investigate how functional group chemistry influences Li/Li⁺ interactions, dissolution behavior, interfacial evolution, and electrochemical accessibility in naphthalene-derived organic anodes. Using naphthalene as a model framework, we systematically compare hydroxylated and carboxylated derivatives through combined computational, electrochemical, spectroscopic, and morphological analyses. Density functional theory (DFT) calculations reveal stronger localized Li⁺ interactions at the vicinal dihydroxyl groups of 2,3-dihydroxynaphthalene (DHN) and the carboxyl group of 2-naphthoic acid (NPA) than in Naph and the monohydroxylated derivatives. However, this enhanced local affinity does not translate into improved electrochemical reversibility. Naphthalene and the monohydroxylated derivatives exhibit limited dissolution, relatively stable interfacial behavior, and sustained cycling performance over 1000 cycles. In contrast, DHN and NPA exhibit greater active material dissolution and more extensive interfacial reconstruction, resulting in reduced electrochemical accessibility and inferior reversibility. This work highlights the importance of balancing favorable Li/Li⁺ interactions with resistance to dissolution and interfacial reconstruction to preserve electrochemically accessible active material in small-molecule organic anodes.