Follow us on X
Follow us on LinkedIn
Subscribe to newsletter

2025

  • Insight into Mo2C Nanoplates Growth by Means of Scanning Electrochemical Cell Microscopy for High-Resolution Electrocatalytic Hydrogen Evolution Activity Mapping

    Geovane Arruda de Oliveira, David E. Sanchez, Alexander J. Sredenschek, Andres Fest, Moonjoo Kim, Carla Santana Santos, Mauricio Terrones, Wolfgang Schuhmann, Daniel Grasseschi
    Molybdenum carbides have emerged as promising catalysts for the hydrogen evolution reaction (HER). While numerous studies have investigated synthesis methods, structural properties, and their application, the understanding of their local electrochemical behavior and the correlation between particle size and activity remains elusive. This study addresses this gap by carrying out a comprehensive investigation of the HER activity of well-defined morphologies and sizes of α-Mo2C nanoplates, grown via chemical vapor deposition.

  • Unraveling the role of supporting electrolytes in organic redox flow battery performance

    Paula Navalpotro, Andreas Mavrantonakis, Rebeca Marcilla
    Redox Flow Batteries (RFBs) are promising energy storage systems to mitigate the fluctuations in renewable energy production and stabilize the electrical grid. One key strategy is the replacement of metallic species with organic redox molecules. With the main focus on molecular engineering so far, the critical role of the supporting electrolyte has been overlooked and neglected. This review highlights the importance of the supporting electrolyte, comprising the solvent and salt, in influencing the performance of organic RFBs.

  • Monitoring chemical processes in redox flow batteries employing in situ and in operando analyses

    Ahmad Alem, Pooria Poormehrabi, Jonas Lins, Lukas Pachernegg-Mair, Christine Bandl, Virginia Ruiz, Edgar Ventosa, Stefan Spirk, Torsten Gutmann
    Redox flow batteries (RFBs) are promising solutions for large-scale stationary energy storage due to their scalability and long cycle life. The efficient operation of RFBs requires a thorough understanding of the complex electrochemical processes occurring during charging and discharging. This review provides an overview and perspective of in situ and in operando analytical techniques to monitor RFBs.

  • Prussian Blue Analogues as Anode Materials for Battery Applications: Complexities and Horizons

    Mario Palacios-Corella, Igor Echevarria, Carla Santana Santos, Wolfgang, Schuhmann, Edgar Ventosa, Maria Ibáñez
    Prussian blue (PB) and Prussian blue analogues (PBAs) are a class of porous materials. So far, PBAs with Cr or Mn as the active site display lower redox potentials and remain significantly underexplored as anode materials. In this publication, we comprehensively analyze the challenges involved in producing and employing PBAs with low redox potentials as active battery materials.

  • Raman spectroelectrochemistry for operando characterization of redox flow batteries

    Lara Lubian, Rubén Rubio-Presa, Virginia Ruiz, Alvaro Colina, Edgar Ventosa
    Advanced in-situ and time-resolved techniques play a critical role to improve performance of Aqueous Organic Redox Flow Batterie (AORFBs). In this publication, the development and implementation of operando Raman spectroscopy is shown for dihydroxyanthraquinone–ferrocyanide alkaline flow battery.

  • Thermodynamic strategies to increase solubility for higher energy density in organic redox flow batteries

    Murilo L. Alcantara, Dinis O. Abranches, Catarina M.S.S. Neves, Rubén Rubio-Presa, Edgar Ventosa, João A.P. Coutinho
    Improving the solubility of redox-active organic molecules (ROMs) in electrolyte solutions is vital for boosting the energy density of redox flow batteries and avoiding precipitation issues. This study explores six thermodynamic strategies to enhance ROM solubility by lowering melting points or activity coefficients.

  • Enhancing the Stability of Aqueous Membrane-Free Flow Batteries: Insights into Interphase Processes

    Paula Navalpotro, Carla Santana Santos, Murilo L. Alcantara, Vanesa Muñoz-Perales, Santiago E. Ibañez, Antonio Martínez-Bejarano, Nomnotho Jiyane, Catarina M. S. S. Neves, Rubén Rubio-Presa, Thomas Quast, Wolfgang Schuhmann, João A. P. Coutinho, Rebeca Marcilla
    This study presents a new aqueous membrane-free flow battery based on a novel aqueous biphasic system with enhanced electrolyte properties. The system uses compatible species exhibiting high partitioning behavior, as demonstrated by computational and experimental analysis. These species prevent parasitic reactions, enabling unprecedented studies of the liquid–liquid interphase and providing valuable insights into advancing this battery technology.

  • Membrane-free redox flow battery: From the idea to the market

    Paula Navalpotro; Jesus Palma; Vanesa Muñoz-Perales; Antonio Martínez-Bejarano; María Victoria Martín-Arroyo; David P. Taylor; Anetta Platek-Mielczarek; Pier Giuseppe Rivano; Federico Paratore; Emilio Dal Re; Rebeca Marcilla
    Due to their efficiency and ability to decouple energy and power density, redox flow batteries (RFBs) are particularly suited to address the rising energy demand and the need for effective energy storage systems. Still, the costs for ion-selective membranes and vanadium-based electrolytes used for those batteries are high. This publication considers and alternative membrane-free flow battery technology that relies on immiscible electrolytes which separate into two distinct liquid phases without the use of a membrane.

  • Efficient Confinement of Solid Capacity Booster Powder as Monolithic Structures for High Performance Redox Mediated Flow Batteries

    Gimena Marin-Tajadura, Yi He, Virginia Ruiz, Edgar Ventosa
    Confinement of solid electroactive materials in the external reservoirs of Redox-Mediated Flow Batteries (RMFB) is of critical importance for the development of this family of battery technologies. Herein, an efficient strategy that is based on a flow-through configuration is proposed.

  • On the Relevance of Static Cells for Fast Scale-Up of New Redox Flow Battery Chemistries

    Lara Lubian, Ruben Rubio-Presa, Roberto, Sanz, Virginia Ruiz, Edgar Ventosa
    The search for organic electroactive molecules suitable in aqueous organic flow batteries requires great efforts not only from an electrochemical perspective but also from an organic synthesis viewpoint. In this work, the relevance of static cells for accelerating the search and helping understand degradation mechanisms is focused on.

  • New non-invasive method to monitor and reverse faradaic imbalance in redox flow batteries

    Miguel Cantera, Koray Cavusoglu, Lara Lubián, Rubén Rubio-Presa, Roberto Sanz, Virginia Ruiz, Jose María Cámara, Edgar Ventosa
    State-of-health monitoring is key for the correct operation of redox flow batteries, which are affected by parasite reactions like Faradaic imbalance. This work proposes a new non-invasive monitoring method based on the minimum derivative of the cell voltage, used as the input that controls a rebalancing device to recover the capacity loss, extending the battery lifetime.

2024

2023

  • Broadening Applicability of the Poor Academic's Method for Reversing Polarity in Redox Flow Cell Cycling

    Gimena Marin-Tajadura, Eduardo Sánchez-Díez, Virginia Ruiz, Edgar Ventosa
    The use of symmetrical cells is becoming popular for the search of new electroactive materials in redox flow batteries. Unfortunately, low-cost battery cyclers, commonly used for electrochemical battery testing, are not compatible with symmetrical cells since they usually cannot apply negative bias voltages needed for symmetrical cells. The insertion of a Ni−Cd battery in the voltage sensing path is a simple and effective methodology to overcome this limitation for certain battery cyclers.

  • Computer-Aided Design of Membrane-Free Batteries Using Conductor-like Screening Model for Real Solvents

    José Pedro Wojeicchowski, Catarina S. Neves, Paula Navalpotro, Rubén Rubio-Presa, Edgar Ventosa, Rebeca Marcilla, Joao A.P. Coutinho
    Redox Flow Batteries (RFBs), particularly Membrane-Free Flow Batteries based on Aqueous Biphasic Systems (ABSs), are a promising technology for stationary energy storage. However, to prevent the crossover of species, the redox-active compounds used in the catholyte and anolyte must be selectively dissolved, which is currently achieved using expensive physical barriers. In this study, an approach was developed to predict the partition coefficient of redox-active compounds in ABSs formed by ionic liquids or polymers, salt, and water using the Conductor-like Screening Model for Real Solvents (COSMO-RS).

  • Unprecedented Aqueous Solubility of TEMPO and its Application as High Capacity Catholyte for Aqueous Organic Redox Flow Batteries

    Eduardo Pedraza, Carlos de la Cruz, Andreas Mavrandonakis, Edgar Ventosa, Rubén Rubio-Presa, Roberto Sanz, Sirugaloor Thangavel Senthilkumar, Paula Navalpotro, Rebeca Marcilla
    Despite the excellent electrochemical properties of non-functionalized 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), its use in aqueous organic redox flow battery (AORFB) is hindered to date due to its insolubility in water. However, in this study, an unprecedented solubility of 5.6 m is demonstrated in an aqueous solution of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), which is 80 times higher than in water (0.07 m). A computational study reveals that the unique interaction between TEMPO and TFSI is essential to achieve this record solubility.

  • On the Tunability of Toxicity for Viologen-Derivatives as Anolyte for Neutral Aqueous Organic Redox Flow Batteries

    Sandra de la Parra, Juan Antonio Tamayo-Ramos, Rubén Rubio-Presa, Daniel Perez-Antolin, Virginia Ruiz, Prof. Roberto Sanz, Carlos Rumbo, Prof. Edgar Ventosa
    Viologen-derivatives are the most widely used redox organic molecules for neutral pH negative electrolyte of redox flow batteries. However, the long-established toxicity of the herbicide methyl-viologen raises concern for deployment of viologen-derivatives at large scale in flow batteries. Herein, we demonstrate the radically different cytotoxicity and toxicology of a series of viologen-derivatives in in vitro assays using model organisms representative of human and environmental exposure, namely human lung carcinoma epithelial cell line (A549) and the yeast Saccharomyces cerevisiae.

  • Operando Scanning Electrochemical Probe Microscopy during Electrocatalysis

    Carla Santana Santos, Bright Nsolebna Jaato, Ignacio Sanjuán, Wolfgang Schuhmann, and Corina Andronescu
    This review focused in the recent progress in operando scanning electrochemical probe microscopy (SEPM) measurements during electrocatalysis. SEPM techniques can disclose the local electrochemical reactivity of interfaces in single-entity and sub-entity studies. The powerful operando SEPM measurements can correlate electrochemical activity with changes in surface properties as well as provide insight into reaction mechanisms. The capabilities of SEPMs are showcased toward toward the reduction and evolution of O2 and H2 and electrochemical conversion of CO2. Emphasis is given to scanning electrochemical microscopy (SECM), scanning ion conductance microscopy (SICM), electrochemical scanning tunneling microscopy (EC-STM), and scanning electrochemical cell microscopy (SECCM).

  • A neutral pH aqueous biphasic system applied to both static and flow membrane-free battery

    Paula Navalpotro, Santiago E. Ibañez, Eduardo Pedraza, Rebeca Marcilla
    In this contribution to the Energy Storage Materials journal new aqueous biphasic electrolytes with near neutral pH and low cost are prepared. Battery performance shows high efficiency, capacity utilization and stability. Thus, this manuscript represents a breakthrough in the membrane-free battery since it ceases to just be a promising idea demonstrated only in static conditions and becomes a real flow battery.

  • A Systematic Study on the Redox Potentials of Phenazine-derivatives in Aqueous Media: A Combined Computational and Experimental Work

    Carlos de la Cruz, Roberto Sanz, Anisley Suárez, Edgar Ventosa, Rebeca Marcilla, Andreas Mavrandonakis
    Phenazines are an emerging class of organic compounds that have been recently utilized in aqueous redox flow batteries, a promising technology for large-scale energy storage. A virtual screening based on density functional theory calculations is used to investigate the redox potentials of around 100 phenazine derivatives in aqueous media containing various electron-donating or electron-withdrawing groups at different positions.

  • Addressing Practical Use of Viologen-Derivatives in Redox Flow Batteries through Molecular Engineering

    Ruben Rubio-Presa, Lara Lubian, Mario Borlaf, Edgar Ventosa, Roberto Sanz
    In practical scenarios, viologen-derivatives face an accelerated degradation in the unavoidable presence of traces of oxygen in large-scale redox flow batteries. Herein, we confirm the primary degradation mechanism and propose a straightforward, cheap, and fast method to evaluate the stability of viologen-derivatives toward this degradation. A new viologen-derivative is designed and synthesized to illustrate how molecular engineering can be used to improve stability.