Engineering potential electrocatalysts for both AEM Electrolyzers and Redox Flow Batteries: Design of experiments at the different scales

• Upscaling materials for electrolysis and energy storage involves intrinsic risks. • A step-oriented DOE is proposed to optimize catalyst structure, morphology and doping. • NiCo 2 O 4 spinel oxide with urchin-like flower shape was selected as starting material. • The sprayed electrodes showed low resistance, durability, low overpotential. • The direct deposited electrode, working without binder, showed high activity and durability. Both water electrolysis and electrochemical energy storage are promising technologies for dealing with the intermittency of green electricity generation. In this work we investigated the possibility of using the same electro-catalyst for hydrogen production by Anion Exchange Membrane Water Electrolysis (AEMWE) and energy storage by Redox Flow Batteries (RFB). A complete experimental campaign was designed to investigate the effects of the catalyst nanostructure and morphology on the electrode performance at different scales. Focus was devoted to the choice of the main factors influencing the catalyst structure, its morphology and electrochemical activity; taking further into account the technique to deposit the catalyst on the Gas Diffusion Layer (GDL) and its integration inside the Membrane Electrode Assembly (MEA). Some results are reported for a spinel-based NiCo 2 O 4 catalyst, chosen as a base nanocomposite to develop more complex materials for both the Oxygen Evolution Reaction (OER) in AEMWE and the positive electrode in Vanadium RFB in the future.