How charge regulation and ion-surface affinity affect the differential capacitance of an electrical double layer

Autor(es)

Quadre, Amanda B. ^[1] ; de Carvalho, Sidney J. ^[1] ; Bossa, Guilherme Volpe ^[1]

Afiliação do(s) autor(es)

^[1] Sao Paulo State Univ UNESP, Dept Phys, Inst Biosci Humanities & Exact Sci, BR-15054000 Sao Jose Do Rio Preto, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Physical Chemistry Chemical Physics; v. 22, n. 32, p. 18229-18238, AUG 28 2020.
• Citações Web of Science: 0

Resumo

The differential capacitance of an electrical double layer is a topic of great importance to develop more efficient and environment-friendly energy storage devices: electric double layer supercapacitors. In addition to the bare electrostatic interactions, recent experimental and computational studies suggest that electrodes covered by ionizable groups do interact selectively with specific ion types, an effect that can increase the maximal conductivity and voltage of a supercapacitor. Inspired by this, in the present work we investigate how ion-specific non-electrostatic interactions modify the differential capacitance of a flat electrode whose surface is covered by ionizable groups subject to a charge regulation process. The incorporation of hydration interactions by means of ion-specific Yukawa potential into the Poisson-Boltzmann theory allows our model to describe different scenarios of ion-surface affinity and, hence, the selective depletion or accumulation of specific ion types close to a charged surface. We obtained larger capacitance values when considering electrodes that favor the accumulation of cations and the depletion of anions. (AU)

• Processo FAPESP: 17/21772-2 - Extensões da Teoria de Poisson-Boltzmann para o estudo da capacitância diferencial de uma dupla camada elétrica
• Beneficiário: Guilherme Volpe Bossa
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 18/22382-6 - Efeitos de regulação de carga e interações não-eletrostáticas sobre a capacitância diferencial de supercapacitores
• Beneficiário: Amanda Beatriz Quadre
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 18/01841-2 - Estudo por Simulação Computacional da Interação entre Polieletrólitos e Macromoléculas
• Beneficiário: Sidney Jurado de Carvalho
• Modalidade de apoio: Auxílio à Pesquisa - Regular