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A Membrane‐Free Redox Flow Battery with Two Immiscible Redox Electrolytes
Author(s) -
Navalpotro Paula,
Palma Jesus,
Anderson Marc,
Marcilla Rebeca
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201704318
Subject(s) - flow battery , redox , vanadium , electrolyte , membrane , battery (electricity) , energy storage , faraday efficiency , chemistry , potassium ion battery , chemical engineering , materials science , inorganic chemistry , electrode , lithium vanadium phosphate battery , power (physics) , thermodynamics , engineering , biochemistry , physics
Flexible and scalable energy storage solutions are necessary for mitigating fluctuations of renewable energy sources. The main advantage of redox flow batteries is their ability to decouple power and energy. However, they present some limitations including poor performance, short‐lifetimes, and expensive ion‐selective membranes as well as high price, toxicity, and scarcity of vanadium compounds. We report a membrane‐free battery that relies on the immiscibility of redox electrolytes and where vanadium is replaced by organic molecules. We show that the biphasic system formed by one acidic solution and one ionic liquid, both containing quinoyl species, behaves as a reversible battery without any membrane. This proof‐of‐concept of a membrane‐free battery has an open circuit voltage of 1.4 V with a high theoretical energy density of 22.5 Wh L −1 , and is able to deliver 90 % of its theoretical capacity while showing excellent long‐term performance (coulombic efficiency of 100 % and energy efficiency of 70 %).