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Tuning the morphology of sulfur–few layer graphene composites via liquid phase evaporation for battery application

A comparative study on sulfur-based composite electrodes comprising different few-layer graphene contents prepared via a facile evaporation method is presented here. The active material production process employed here, exploring different sulfur–few layer graphene ratios, enabled tuning and optimiz...

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Detalles Bibliográficos
Autores principales: Venezia, Eleonora, Carbone, Lorenzo, Bonaccorso, Francesco, Pellegrini, Vittorio
Formato: Online Artículo Texto
Lenguaje:English
Publicado: RSC 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9418723/
https://www.ncbi.nlm.nih.gov/pubmed/36131758
http://dx.doi.org/10.1039/d1na00733e
Descripción
Sumario:A comparative study on sulfur-based composite electrodes comprising different few-layer graphene contents prepared via a facile evaporation method is presented here. The active material production process employed here, exploring different sulfur–few layer graphene ratios, enabled tuning and optimization of the sample morphology, as confirmed via a scanning electron microscopy study. The results reveal that the graphene content is a crucial parameter yielding an optimized morphology of spherical particles composed of an elemental sulfur inner core covered by the carbonaceous compound. The electrodes are characterized in lithium metal half-cells in terms of cyclic voltammetry, galvanostatic cycling tests, rate capability and electrochemical impedance spectroscopy. Moreover, the lithium-ion diffusion coefficients of each sample are obtained by the Randles–Sevcik equation in order to evaluate the reliability of the electrochemical processes. The lithium metal half-cell with the sulfur carbon composite active material exploiting a spherical particle morphology delivers a high specific capacity of 950 mA h g(−1) after 100 cycles at C/4 with a coulombic efficiency of 98%. An optimized sample, tuned in terms of sulfur content and morphology, shows superior performance, exhibiting capacities of 1128 mA h g(−1) and 842 mA h g(−1) over 80 cycles at C/4 and 2C, respectively.