Simulações computacionais de supercapacitores com modelos coarse-grained
Arquivos
Data
2022-11-21
Autores
Silva, Isabel Amaral da [UNIFESP]
Orientadores
Siqueira, Leonardo José Amaral de [UNIFESP]
Tipo
Trabalho de conclusão de curso de graduação
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Resumo
Líquidos iônicos são sais fundidos em temperaturas inferiores a 100 °C e têm sido alvo de intensa investigação na Academia como eletrólitos para supercapacitores. Modelos coarse-grained têm sido amplamente utilizados em vários estudos de lipídios como uma forma de aumentar a escala espaço-temporal de amostragem em simulações computacionais. Em modelos coarse-grained, alguns grupos de átomos nas moléculas que formam os líquidos iônicos, por exemplo, são suprimidos e representados por esferas. Embora haja uma perda de descrição molecular, os modelos coarse-grained permitem o aumento no tempo de amostragem devido ao aumento no tempo de integração das equações de movimento e aumentam a escala espacial da simulação, por exemplo, caixas de simulação podem passar de 4 para 10 nm. Neste trabalho, misturas de líquidos iônicos, com modelos coarse-grained, foram utilizadas como eletrólito em supercapacitores planos e porosos de grafeno, também em modelo coarse-grained. Os supercapacitores com eletrodo plano apresentaram resultados condizentes aos obtidos por modelo atomístico e o tamanho da área do eletrodo não mostrou efeitos consideráveis sobre as propriedades do supercapacitor. Já para as simulações com eletrodos porosos, o sistema poroso de 3 poros diferentes tem mecanismos de carregamento diferentes para cada poro e possui um desempenho intermediário em relação aos de poros de tamanho único.
Ionic liquids are molten salts at temperatures below 100 °C and have been the subject of intense research at the Academy as electrolytes for supercapacitors. Coarse-grained models have been widely used in various lipid studies as a way to increase the spatio-temporal scale of sampling in computer simulations. In coarse-grained models, some groups of atoms in the molecules that form ionic liquids, for example, are suppressed and represented by spheres. Although there is a loss of molecular description, coarse-grained models allow an increase in sampling time due to an increase in the integration time of the equations of motion and an increase in the spatial scale of the simulation, for example, simulation boxes can go from 4 to 10 nm. In this work, mixtures of ionic liquids, with coarse-grained models, were used as electrolytes in flat and porous graphene supercapacitors, also in a coarse-grained model. The supercapacitors with flat electrodes showed results consistent with those obtained by the atomistic model and the size of the electrode area did not show considerable effects on the properties of the supercapacitor. As for the simulations with porous electrodes, the porous system of 3 different pores has different charging mechanisms for each pore and has an intermediate performance in relation to the one-size pores.
Ionic liquids are molten salts at temperatures below 100 °C and have been the subject of intense research at the Academy as electrolytes for supercapacitors. Coarse-grained models have been widely used in various lipid studies as a way to increase the spatio-temporal scale of sampling in computer simulations. In coarse-grained models, some groups of atoms in the molecules that form ionic liquids, for example, are suppressed and represented by spheres. Although there is a loss of molecular description, coarse-grained models allow an increase in sampling time due to an increase in the integration time of the equations of motion and an increase in the spatial scale of the simulation, for example, simulation boxes can go from 4 to 10 nm. In this work, mixtures of ionic liquids, with coarse-grained models, were used as electrolytes in flat and porous graphene supercapacitors, also in a coarse-grained model. The supercapacitors with flat electrodes showed results consistent with those obtained by the atomistic model and the size of the electrode area did not show considerable effects on the properties of the supercapacitor. As for the simulations with porous electrodes, the porous system of 3 different pores has different charging mechanisms for each pore and has an intermediate performance in relation to the one-size pores.