Development and Challenges of Biphasic Membrane‐Less Redox Batteries

Abstract

Ion exchange membranes (IEMs) play important roles in energy generation and storage field, such as fuel cell, flow battery, however, a major barrier in the way of large‐scale application is the high cost of membranes (e.g., Nafion membranes price generally exceeds USD$ 200 m−2). The membrane‐less technology is one of the promising approaches to solve the problem and thus has attracted much attention and been explored in a variety of research paths. This review introduces one of the representative membrane‐less battery types, Biphasic membrane‐less redox batteries that eliminate the IEMs according to the principle of solvent immiscibility and realizes the phase splitting in a thermodynamically stable state. It is systematically classified and summarizes their performances as well as the problems they are suffering from, and then several effective solutions are proposed based on the modification of electrodes and electrolytes. Finally, special attention is given to the challenges and prospects of Biphasic membrane‐less redox batteries, which could contribute to the development of membrane‐less batteries.

An Ultra‐Low Self‐Discharge Aqueous|Organic Membraneless Battery with Minimized Br2 Cross‐Over

“…[11] In hybrid BLAM, such as Zn-based systems, the combination of ion-exchange membrane plus high-concentration electrolyte additives can effectively reduce the cross-over [12] yet sacrifices with a drastic increase in the capital cost (≈50%). [13] At the same time, the industry prefers cost-effective porous membranes/membraneless designs [14] in which cross-over is inevitable.…”

Principles and Design of Biphasic Self‐Stratifying Batteries Toward Next‐Generation Energy Storage

“…Biphasic self-stratifying batteries (BSBs) provide a promising alternative for future massive-scale energy storage solutions. [20,21] The Scheme of a typical BSB architecture is drawn in Figure 1a. Compared with conventional RFBs, while inheriting the structure advantages of RFBs to decouple cathode/anode, the most distinctive feature of BSBs is their subversive membraneless structure.…”

Boosting the cell voltage in biphasic flow batteries via Galvani potential difference

“…3,4 The evolving energy storage landscape has led to the emergence of biphasic flow batteries, employing two immiscible electrolytes, which utilize organic solvents for a higher cell voltage compared to water-based batteries. [5][6][7][8] Unlike their monophasic counterparts, biphasic flow batteries introduce a novel approach by employing two immiscible liquid phases (immiscible negolyte and posolyte), often a combination of organic and aqueous phases, [5][6][7][8] two organic phases separated by an aqueous phase 9,10 or more recently also two aqueouscontaining phases. 6 Recently, also all-organic biphasic batteries have been proposed.…”