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Mild pH-decoupling aqueous flow battery with practical pH recovery

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Xi, Dawei ; Alfaraidi, Abdulrahman M. ; Gao, Jinxu ; Cochard, Thomas ; Faria, Luana C. I. ; Yang, Zheng ; George, Thomas Y. ; Wang, Taobo ; Gordon, Roy G. ; Liu, Richard Y. ; Aziz, Michael J.
Número total de Autores: 11
Tipo de documento: Artigo Científico
Fonte: NATURE ENERGY; v. 9, n. 4, p. 12-pg., 2024-02-19.
Resumo

Establishing a pH difference between the two electrolytes (pH decoupling) of an aqueous redox flow battery (ARFB) enables cell voltages exceeding the 1.23 V thermodynamic water-splitting window, but acid-base crossover penalizes efficiency and lifetime. Here we employ mildly acidic and mildly alkaline electrolytes to mitigate crossover, achieving high round-trip energy efficiency with open circuit voltage >1.7 V. We implemented an acid-base regeneration system to periodically restore electrolytes to their initial pH values. The combined system exhibited capacity fade rate <0.07% per day, round-trip energy efficiency >85% and approximately 99% Coulombic efficiency during stable operation for over a week. Cost analysis shows that the tolerance of acid-base crossover could be increased if the pH-decoupling ARFB achieved a higher voltage output and lower resistance. This work demonstrates principles for improving lifespan, rate capability and energy efficiency in high-voltage pH-decoupling ARFBs and pH recovery concepts applicable for pH-decoupling systems. (AU)

Processo FAPESP: 21/14537-2 - Eletrodos de carbono de baixo custo e alto desempenho para aplicação em bateria de fluxo redox
Beneficiário:Luana Cristina Italiano Faria
Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado Direto
Processo FAPESP: 19/21089-6 - Superfícies de carbono para aplicação em baterias orgânicas: propriedades estruturais da interface hidrogel/eletrólito/eletrodo
Beneficiário:Luana Cristina Italiano Faria
Modalidade de apoio: Bolsas no Brasil - Doutorado Direto