New paper in Energy & Environmental Materials: Dry Electrode Processing for Free-Standing Supercapacitor Electrodes with Longer Life, Higher Volumetric Outputs, and Reduced Environmental Impact.

Our research explores the benefits of dry electrode processing for supercapacitors. As one of the pioneering energy storage systems to adopt dry electrode processing (e.g., through [formerly] Maxwell), supercapacitors have shown significant advancements in this area. Our study follows up with this processing technology and demonstrates notable improvements in electrode lifespan, volumetric energy density, and environmental sustainability by utilizing dry processing techniques. By bypassing conventional solvent-based methods, we achieved a 28% increase in energy density and a reduction in manufacturing-related CO2 emissions, while also extending the lifespan of supercapacitors across various electrolytes, including organic, ionic liquids, and quasi-solid state.

In the broader context, this research contributes to the ongoing efforts to enhance energy storage technologies. Supercapacitors are crucial for bridging the gap between batteries and capacitors, offering rapid charge/discharge capabilities and long cycle life. The adoption of dry electrode processing can advance their sustainability and, at the same time, yield a better performance per the more intricate particle-particle contact and ability to obtain even ultra-thick electrodes (in our work: up to 700 µm).

Team Jena: Marius Hermesdorf, Desirée Leistenschneider; Team Saarbrücken: Emmanuel Pameté, Jean Gustavo De Andrade Ruthes, Anna Seltmann, Delvina Tarimo (PhD).

Making an electrode is art and science: The relevance of electrode preparation optimization and potential window maximization for high-rate lithium-ion batteries. Our new paper in Advanced Energy and Sustainability Research optimizes lithium titanate (LTO) anodes for lithium-ion batteries. By tweaking the dry and wet mixing processes during electrode fabrication, we achieved remarkable improvements in capacity retention, especially at high charge rates. Employing an extended potential window of 0.01-3.00 V vs Li+/Li, a high capacity of about 290 mAh/g at 0.1 A/g was obtained. Specifically, using the best-performing electrode processing in our work, we obtained a capacity of 232 mAh/g at 1C with a capacity retention of 80% after 300 cycles at a rate of 34C (68% after 1000 cycles). These results highlight the importance of control over particle dispersion in maximizing electrode performance.

This work underscores the potential of LTO as a durable and safe option for applications where high power and long cycle life are critical, such as electric vehicles and grid storage. By reducing solvent usage by up to 50%, our study shows the potential of cost and material savings per optimized processing.

Many thanks to all authors: Amir Haghipour, Stefanie Arnold, Jonas Oehm, Dominik Schmidt, Lola Gonzalez-Garcia, Dr. Hitoshi Nakamura, Tobias Kraus, and Volker Knoblauch

New paper published on “Multi-scale circuit model bridges molecular modeling and experimental measurements of conductive metal-organic framework supercapacitors” in Physical Chemistry Chemical Physics.

New open access paper published in ACS Applied Materials & Interfaces on “Understanding Rate and Capacity Limitations in Li-S Batteries Based on Solid-State Sulfur Conversion in Confinement”. This study explores how solid-state sulfur conversion within carbon nanopores enhances the performance of lithium-sulfur batteries. Key parameters relate to cathode-electrolyte interphase (CEI) formation, pore size, and material design.

Key findings from our study:

  • Nanopore engineering: Small nanopores (<0.8 nm) promote efficient CEI formation, improving charge transfer and enabling solid-state sulfur conversion without polysulfide dissolution.
  • Rate limitation insights: Charge transfer between sulfur and carbon dominates rate limitations, particularly during charging, while lithium-ion transport plays a secondary role.
  • Material utilization: Optimized sulfur-to-carbon ratio maximizes the capacity by balancing pore filling and reaction kinetics.
  • Advanced methodologies: Techniques like operando SANS and XRD provide evidence for the stability of solid-state conversion processes and the amorphous nature of sulfur products within nanopores.

This work is an outcome of the Slovenian-Swiss-Austrian-German ALISA project (Advanced Lithium-Sulfur batteries with ultramicroporous carbons), supported by the European Commission Horizon 2020 program and various national funding agencies (including Bundesministerium für Bildung und Forschung). It contributes to the broader effort of advancing sustainable and high-energy-density battery systems, aligning with global clean energy goals.
Thank you for the great collaboration Ayça Şenol Güngör, Jean-Marc von Mentlen, Jean Gustavo De Andrade Ruthes, Francisco J. García-Soriano, Sara Drvarič Talian, Lionel Porcar, Alen Vizintin, Vanessa Wood, and Christian Prehal

Our latest research in Energy & Environmental Science explores an eco-friendly, high-performance lithium-ion anode made from self-assembled organic nanowires. By evaporating water on a copper current collector, we achieved a nanowire network without harmful solvents, enhancing lithium-ion diffusion and storage capabilities. The result? The self-assembled organic nanowire anode delivers a remarkable lithium storage capacity of up to 1888 mA h/g at 0.1 A/g, retaining 508 mA h/g even at a high current rate of 10 A/g. In lithium-ion capacitors, it achieves a specific energy of 156 W h/kg at 0.34 kW/kg and maintains 60.2 W h/kg at 19.4 kW/kg, outperforming many state-of-the-art systems.

This Czech-German research collaboration was carried out by Ievgen Obraztsov, Rostislav Langer, Jean G. A. Ruthes, Volker Presser, Michal Otyepka, Radek Zboril, and Aristides Bakandritsos.

Our new paper, Electrochemical recycling of lithium-ion batteries: Advancements and future directions, is now available online at the Wiley journal EcoMat. Our review provides a perspective of different recycling techniques currently used for lithium-ion batteries. We begin by reviewing the more established pyrometallurgical and hydrometallurgical methods, which have been widely adopted in industrial applications. These methods, while effective, often involve high energy consumption and the use of chemical reagents, raising concerns about their long-term sustainability.

Building on this foundation, we focus on emerging electrochemical approaches, which offer a more sustainable alternative by using electricity to recover valuable metals like lithium, cobalt, and nickel. This method reduces the need for harmful chemicals and promises lower energy demands, especially when powered by renewable energy sources. However, despite these advantages, electrochemical recycling is not without its challenges. Our paper critically examines key issues such as scalability and selectivity. We emphasize the need for further research to address these obstacles and unlock the full potential of electrochemical recycling to improve metal recovery efficiency while minimizing waste and environmental impact.

In the broader context of the energy transition, efficient battery recycling is becoming increasingly important. As demand for electric vehicles and renewable energy storage rises, ensuring the sustainable recovery of metals like lithium, cobalt, and nickel is crucial. While electrochemical methods are promising, significant technical challenges remain to be addressed before these processes can be widely adopted. We believe our work contributes to a deeper understanding of the current landscape and offers insights into future directions.

New paper published on cation separation during flow electrode capacitive deionization in Desalination. This work is about improving water treatment and resource recovery through selective ion removal using flow electrode capacitive deionization (FCDI). We explore separating specific cations like calcium and magnesium from multi-ion solutions, helping to optimize water desalination processes. Our data show that while the overall ion separation order follows a universal order, the kinetics (down to full ion depletion) can be adjusted as a function of carbon mass loading, presence or absence of conductive additive, and flow rate.

New paper published in Nature Communication. This highly collaborative work (spearheaded by Dr. Gündoğ Yücesan) presents polyphosphonate covalent organic frameworks (COFs) constructed via P-O-P linkages, synthesized through a one-step condensation reaction. This process involves heating a hydrogen-bonded precursor made from phenylphosphonic acid and porphyrin, without chemical reagents. At temperatures above 210 °C, the COF transforms into an amorphous microporous structure due to P-O-P bond oligomerization, confirmed by 31P NMR. The COF shows excellent stability in water, water vapor, and in 0.5 M Na2SO4 electrolyte, filling a gap in COF literature for stable, microporous materials. Additionally, its narrow pores effectively capture CO2, with a sustainable synthesis route.

New paper published on “Life after death: Re-purposing end-of-life supercapacitors for electrochemical water desalination” in Batteries & Supercaps.

Even the best supercapacitor, at some point, will reach its end-of-life. With limited amounts of precious elements (unlike lithium-ion batteries), elemental extraction of the active material’s components is not really attractive for supercapacitors. More interesting is to see the direct recycling of the active component, meaning mostly activated carbon in its various forms. But what else can we do with nanoporous carbons from spent supercapacitors?

Our work explores the re-purposing of end-of-life commercial supercapacitors as electrochemical desalination cells, using them for capacitive deionization. The research demonstrates that the carbon electrodes from disassembled supercapacitors can be modified and effectively used for water desalination via capacitive deionization. The modifications ranged from NaOH-etching to CO2 activation, showing varying degrees of efficiency and stability in desalinating low-salinity water. As a concept study, we show limitations and perspectives toward re-purposing in the context of electrochemical desalination.

New research paper from our collaboration with Michael Naguib: “Nitrogen-Doped Graphene-Like Carbon Intercalated MXene Heterostructure Electrodes for Enhanced Sodium- and Lithium-Ion Storage” published in Advanced Science.

We’ve developed a novel N-doped graphene-like carbon intercalated Ti3C2Tx (NGC-Ti3C2Tx) heterostructure. But wait… why would one want to add something in-between the MX-layers, the wonderful interlayer space that should host lithium- and sodium-ion for battery application?


By adding a thin carbon layer, we do not block ion uptake but create additional intercalation sites above and beneath the carbon layer! This yields a reversible specific capacity of 305 mAh/g for sodium-ion batteries and 400 mAh/g for lithium-ion batteries.

Our findings address the critical challenge of low reversible capacity in many MXenes, making a contribution to the field of energy storage materials. By intercalating thin carbon layers into MXene, we provide a promising route to enable enhanced capacity for MXene battery electrodes, backed up both by experimental data and modeling data.

A heartfelt thanks to the wonderful international (co)authors KUN LIANG, Tao Wu, Sudhajit Misra, Chaochao Dun, Samantha Husmann, Kaitlyn Prenger, Jeffrey J. Urban, Raymond Unocic, De-en Jiang and Michael Naguib.

New paper on solvation effects inside carbon nanopores during electrosorption published in Carbon.

Our British-German study explores the solvation effects on ion adsorption and electrosorption within carbon micropores, employing nuclear magnetic resonance (NMR) spectroscopy to gain insights. Our data investigate how ionophilicity and ionophobicity – the tendency of ions to be uptaken by uncharged nanopores – affect the partitioning behavior of ions. The nanopore diameter significantly influences ion adsorption, with narrower pores creating higher barriers for ion entry. The research also reveals that ion-specific solvation effects impact on the charge storage mechanism, with ionophilic systems favoring counter-ion adsorption, while ionophobic systems tend toward co-ion ejection under applied voltage.

In a broader context, this work contributes to the ongoing efforts to enhance the efficiency of energy storage technologies, especially fast charge/discharge capable supercapacitors. By unraveling the interactions between ions and carbon nanopores, the research provides insights that could inform the development of more effective materials for supercapacitors and capacitive deionization, key components in sustainable energy systems.

Acknowledgments: Ryan J. Bragg (Lancaster University), Kieran Griffiths (Lancaster University), Imgon Hwang (The University of Manchester), Mantas Leketas (The University of Manchester), Kacper Polus (The University of Manchester), Robert Dryfe (The University of Manchester), and of course John M. Griffin (Lancaster University).#

New paper published in Chemical Engineering Journal on “A sustainable approach: Repurposing harmful algal biomass as carbon-based catalysts for nitrogen fertilizer electrosynthesis from nitrate and CO2“.

📜 Our research focuses on repurposing harmful algal blooms (HABs) biomass into carbon-based catalysts, specifically Cu1Mo1/NC, for the electrosynthesis of nitrogen fertilizers (urea and ammonia) from nitrate and CO2. This method not only addresses the environmental issue of HABs but also offers a sustainable approach to fertilizer production. The Cu1Mo1/NC catalyst demonstrated a high yield rate of 772 μg/h/mg(cat) for urea and 1531 μg/h/mg(cat) for ammonia, with a Faradaic efficiency of 68.4%.

🌐 The production of nitrogen fertilizers, essential for global food security, is currently dominated by energy-intensive processes such as Haber-Bosch, which contribute significantly to global CO2 emissions. Our approach explores how to mitigate these environmental impacts by using renewable resources and recycling waste. An approach like ours could potentially reduce CO2 emissions by millions of tons annually, equivalent to the emissions of hundreds of thousands of people.

🌱This study is a step towards sustainable agriculture, integrating renewable energy and waste recycling. Although the current system’s efficiency needs improvement to achieve positive profit and net CO2 emission reduction, it paves the way for future advancements in green and low-carbon fertilizer synthesis.

👩‍🔬👨‍🔬 Thanks to all of our partners: He Wang, Shuaishuai Man (who visited our laboratory 2021-2022), Han Wang, and Qun Yan.

New paper published on “Freestanding Films of Reduced Graphene Oxide Fully Decorated with Prussian Blue Nanoparticles for Hydrogen Peroxide Sensing” in ACS Omega.

This work explores freestanding graphene/Prussian blue (PB) electrodes for detecting hydrogen peroxide (H2O2). Using a two-step method, we synthesized reduced graphene oxide/PAni/Fe2O3 freestanding films, followed by electrochemical deposition of PB nanoparticles. This approach balances the structure of the electrodes with their electrochemical performance for H2O2 sensing.

Thanks to all authors for this Brazilian-German collaboration: Vitor H. N. Martins, Monize M. da Silva, Daniel A. Gonçalves, Samantha Husmann, and Victor H. R. Souza.

New review article “Functional gel-based electrochemical energy storage” published Chemistry of Materials. This paper reviews the research field of gel polymer electrolytes (GPEs), which combine the ionic conductivity of liquid electrolytes with the mechanical stability of solid materials. GPEs are versatile materials in various electrochemical applications, including sensors, actuators, and energy storage devices. These quasi-solid materials can withstand significant mechanical stress, making them attractive for flexible and wearable electronics. This collaborative work was done by Jean Gustavo De Andrade Ruthes, Stefanie Arnold, Kaitlyn Prenger, Ana C. Jaski, Vanessa Klobukoski, and Izabel C. Riegel-Vidotti.

New paper published in Energy & Environmental Materials. A few years ago, then-PhD-student Zhang Yuan explored with us the adoption of a fuel cell for continuous water desalination. Basically, a fuel cell can be “fooled” to desalinate an inflowing water stream by replacing the common proton exchange membrane with a flow channel, contained within a pair of an anion and a cation exchange membrane. Thereby, while consuming fuel (e.g., hydrogen and oxygen), electricity is generated and water desalted all at once. Now, we have moved one step further: making fuel cell desalination lithium-ion selective for direct lithium-ion extraction from seawater or mine water (other water media work too).

Our team, lead by Cansu Kök, and with Lei Wang, Jean Gustavo De Andrade Ruthes, Antje Quade (from the Leibniz Institute for Plasma Science and Technology (INP Greifswald) e.V.), and Matthew Suss (from Technion – Israel Institute of Technology; now at Form Energy), has developed the first-ever fuel cell system designed specifically for continuous lithium-ion extraction. This approach utilizes a lithium superionic conductor membrane alongside advanced electrodes to enhance efficiency and environmental sustainability.

A titania-coated electrode in our fuel cell achieves a 95% lithium-ion purity and produces 10.23 Wh of energy per gram of lithium. Thanks to atomic layer deposition, we’ve significantly improved the electrode’s uniformity, stability, and electrocatalytic activity, maintaining stability even after 2000 cycles.

The IOP Journal “Materials Futures” has included our paper led by alumnus Qingsong Wang in the collection of the “Materials Futures 2023 Best Paper Award”.

J. Wang, S.L. Dreyer, K. Wang, Z. Ding, T. Diemant, G. Karkera, Y. Ma, A. Sarkar, B. Zhou, M.V. Gorbunov, A. Omar, D. Mikhailova, V. Presser, M. Fichtner, H. Hahn, T. Brezesinski, B. Breitung, Q. Wang, P2-type layered high-entropy oxides as sodium-ion cathode materials, Materials Futures 1(3) (2022) 035104.

https://iopscience.iop.org/journal/2752-5724/page/news-and-editorial

New paper in Carbon on hydrogen densification in carbon nanopore confinement: Insights from small-angle neutron scattering using a hierarchical contrast model from our long-term collaboration with Oskar Paris (Montanuniversität Leoben).

New paper published in Langmuir on emerging frontiers in multichannel membrane capacitive deionization. Spearheaded by our group alumni Choonsoo Kim, together with Hyunjin Kim, Seonghwan Kim, and Byeongho Lee from Kongju National University, our joint work dives deep into the advancements and future prospects of MC-MCDI technology. We explore how this innovative approach not only pushes the boundaries of efficiency and sustainability in addressing global water scarcity but also sets new benchmarks for electrochemical desalination.

New battery published in ACS Applied Materials & Interfaces on hybridization of carbon spherogels with titanium oxide and sulfur enables high performance lithium-ion battery electrodes. As a result from our research project with Michael Elsaesser from the Paris Lodron Universität Salzburg, we introduce a novel approach to enhancing lithium-ion battery electrodes. We have successfully combined titanium oxide and sulfur with carbon spherogels, achieving high performance in terms of stability and capacity. Our method resulted in electrodes combining high charge storage capacity and electrical conductivity, while maintaining a core-shell morphology. The process involved producing carbon spheres encapsulating titania and sulfur using a template-assisted sol-gel route, followed by thermal treatment with hydrogen sulfide gas. This treatment fully preserved the microporous hollow sphere architecture of the carbon shells, facilitating sulfur deposition and titania crystal protection.

New review paper published in Desalination. Our manuscript examines various Direct Lithium Extraction (DLE) technologies, a response to increasing lithium demand driven by its extensive use in batteries for diverse applications. Traditional lithium extraction methods, including mining and evaporation ponds, pose significant environmental challenges and may not suffice to meet global demand. DLE offers a potentially more efficient and sustainable alternative, akin to the impact of shale extraction on the oil industry. This study provides a comprehensive analysis of DLE techniques such as adsorption, ion exchange, membranes, direct carbonation, and electrochemical processes. It assesses their operational fundamentals, advantages, and limitations. The research aims to evaluate DLE’s capacity for efficient and sustainable lithium recovery amidst rising energy sector demands, addressing associated challenges like cost, environmental impact, and scalability. The findings intend to enrich understanding of DLE’s potential and hurdles, guiding future research in this critical technological area.