Vapor-diffusion controlled sol-gel synthesis of flaky lithium vanadium oxide and Its electrochemical behavior
Abstract
Effectively modifying an existing synthesis method for materials can prove as useful as developing a new one. In this work, we revisited a conventional sol−gel synthesis of lithium vanadium oxide, a promising electrode material for rechargeable lithium batteries. Employing a kinetically controlled, vapor diffusion strategy (in which ammonia vapor was slowly diffused into the solution), we modified the conventional method to obtain a thin, flaky, lithium vanadium oxide with an average thickness of 120 nm. In comparison, material prepared by the conventional sol−gel route (in which aqueous ammonia was dropwise added to the solution) exhibited an agglomeration of irregular particles with a typical size of 10 μm. When evaluated as cathode material for rechargeable lithium batteries, this flaky material displayed a stable, reversible capacity of 250 and 115 mAh/g at discharge rates of 0.1 C and 2 C, respectively, considerably better than the agglomerated sample. The reasons for this improved performance were investigated by evaluating the electrochemical reaction kinetics, morphological and structural stability using cyclic voltammetry, scanning electron microscopy, and X-ray diffraction.