Renewable energy sources have been a topic of ever-increasing interest, not least due to escalating environmental changes. The significant rise of research into energy harvesting and storage over the years has yielded a plethora of approaches and methodologies, and associated reviews of individual aspects thereof. Here, we aim at highlighting a rather new avenue within the field of batteries, the (noaqueous) all-organic redox-flow battery, albeit seeking to provide a comprehensive and wide-ranging overview of the subject matter that covers all associated aspects. This way, subject matter on a historical perspective, general types of redox-flow cells, electrolyte design and function, flow kinetics, and cell design are housed within one work, providing perspective on the all-organic redox-flow battery in a broader sense.

As 3D‐printing is becoming increasingly accessible, its application towards more sustainable and flexible design strategies for chemical processes also grows substantially. Redox‐flow batteries (RFBs) are recognized as one of the possible next generation energy storage solutions, owing to the inherent decoupling of power and energy, yet the capital costs involved produce a high barrier to enter the field. Here, we demonstrate a full digital blueprint for printing one's own RFB, that can enable more (organic chemistry) contributions to the field. At the time of writing, the combined costs of only the RFB cell total around 60 €, which is less than commercially available RFB cells by a great margin. The cyclic voltammetry, impedance spectroscopy and potentiostatic cycling experiments exemplified by the K₄[Fe^II(CN)₆]|K₃[Fe^III(CN)₆] redox‐pair for aqueous, and ferrocene|ferrocenium for organic electrolytes, validate the stability of the technical lab‐scale design and provides benchmark values for reproduction.

Redox flow batteries (RFBs) are a promising technology for grid energy storage based on their high potential for scalability, design flexibility, high efficiency, and long durability, hence great effort has been invested in this area of research. However, due to the large differences in lab‐scale RFB cell design and construction as well their operational performance, fundamental studies on innovative RFB components (e.g., active materials, separators, additives) compare poorly due to the lack of standard setups, settings, and procedures. This work introduces an experimental calibration route for aqueous as well as nonaqueous RFBs based on a simple mass transport model using molar fluxes, enabling one to compare dissimilar lab‐scale RFB cell setups by introducing several RFB parameters: First, K1, which summarizes the operating parameters of an RFB to identify the critical ratio (K1_critical) needed for efficient charge–discharge cycling using a simple overvoltage and charge efficiency evaluation; second, the RFB cell constant ζ, quantifying the influence of a lab‐scale RFB setup on its performance; and finally, K2, ultimately enabling full comparison of (idealized) K1_critical operating parameters across RFB cell setups.