Irreversibility and Structural Distortion in Organic and Inorganic Fullerenes Arising from Electrochemical Cycling of Alkali-Metal-Ions.

While large interlayer spacing allows for Na⁺ and K⁺ ion storage in transition metal dichalcogenide (TMD) based electrodes, side reactions, and volume change leading to pulverization of crystalline structure are persistent challenges for employing these materials in next-generation devices. Here in this study, we first investigate if irreversibility due to structural distortion resulting in poor cycling stability is also apparent in the case of quantum confined organic and inorganic (TMDs; such as MoS₂) fullerenes. To address these problems, we propose upper and lower voltage cut-off experiments to limit specific reactions. Differential capacity curves and derived surface plots highlight the continuation of reactions when a high upper cut-off technique is applied, indirectly suggesting the restriction of structural dissolution. Furthermore, structural preservation in half-cell electrodes during Li⁺, Na^+, or K⁺ storage delivered better capacity retention with stable performance and higher coulombic efficiency, laying the ground for future works.