Alexandru Vlad

Alexandru Vlad
Université Catholique de Louvain - UCLouvain | UCLouvain · Department of Electrical Engineering

Doctor of Philosophy
Assistant Professor of Chemistry Université catholique de Louvain https://vladgroup.org

About

122
Publications
22,790
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2,723
Citations
Citations since 2017
51 Research Items
1877 Citations
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20172018201920202021202220230100200300400
20172018201920202021202220230100200300400
20172018201920202021202220230100200300400
Introduction
material science, nanoengineering, energy applications, batteries
Additional affiliations
October 2010 - present
Université Catholique de Louvain - UCLouvain
Position
  • frs fnrs
March 2010 - September 2010
Rice University
Position
  • PostDoc Position
October 2009 - January 2010
Chalmers University of Technology
Position
  • PostDoc Position

Publications

Publications (122)
Article
Li-ion microbatteries are the frontline candidates to fulfill the requirements of powering miniature autonomous devices. However, it still remains challenging to attain the required energy densities of > 0.3mWh/cm-2µm-1 in a planar configuration. To overcome this limitation, 3D architectures of LIMBs have been proposed. However, most deposition tec...
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As the demand for electrification of means of transportation and storage of electrical energy for later use is skyrocketing, rechargeable Li-ion batteries (LIBs) are at the heart of this revolution. Acknowledging the carbon footprints, environmental concerns and cost of the commercial cathode materials, this is the high time to advocate sustainable...
Article
Silicon is regarded as one of the most promising anode candidates for next-generation Li-ion batteries because of its high theoretical capacity (4200 mAh g⁻¹). However, the main challenge for the practical application of Si anodes is the huge volume change during (de)alloying with lithium, which leads to the pulverization of the active material and...
Article
Organic phosphates have been widely used as fire-retardant additives/co-solvents to improve the Li-ion electrolyte safety. However, these solvents show poor compatibility with low potential electrodes and cannot work efficiently as sole solvent at low salt concentration. The utilization of high concentration electrolytes was shown to improve the in...
Article
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Coordination polymers (CPs) made of redox-active organic moieties and metal ions emerge as an important class of electroactive materials for battery applications. However, the design and synthesis of high voltage alkali-cation reservoir anionic CPs remains challenging, hindering their practical applications. Herein, we report a family of electrical...
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The high volumetric stack energy density (∼ 750Wh L−1) is a must for grasping the practical application of electric vehicles with more than 100 km per day driving range. Such achievement requires significant advances in state-of-the-art battery technologies. The anode-free, derived from the metal-battery concept, germinates as one of the future pot...
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Sodium and iron make up the perfect combination for the growing demand for sustainable energy storage systems, given the natural abundance and sustainability of the two building block elements. However, most sodium–iron electrode chemistries are plagued by intrinsic low energy densities with continuous ongoing efforts to solve this. Herein, the che...
Article
Controlling redox activity of judiciously appended redox units on a photo‐sensitive molecular core is an effective strategy for visible light energy harvesting and storage. The first example of a photosensitizer ‐ electron donor coordination compound in which the photoinduced electron transfer step is used for light to electrical energy conversion...
Article
Doping carbonaceous materials are regarded as prospective cathode candidates for high‐performance lithium‐sulfur batteries. In this study, we construct a dual functional modification system, including iodine‐doped soft carbon (I‐SC) and iodine functional separator for Li‐S batteries. The formation of C‐I bonds in the carbon skeleton increases the c...
Preprint
Full-text available
In the rising advent of organic Li-ion cathodes with practical characteristic of being air-stable while in the reduced lithium-reservoir form, we report herein a new class of organic Li-ion positive electrode materials - the conjugated oximate lithium salts. The solid-phase electrochemistry of first five examples of the oximate class, including cyc...
Article
Sodium‐ion batteries are considered as the immediate sustainable alternative to lithium‐ion systems. To reduce the competitiveness gap, improved performances and better understanding of sodium storage, especially of new phases based on sustainable materials, are further required. In this work, we provide advanced investigation of the structure and...
Article
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Preparation, analysis and lithium storage performance of a series of nitrogen‐doped carbon nanotube sponges (CNX) is presented in this work. The synthesis was performed using an aerosol‐assisted chemical vapor deposition (AACVD) in a bi‐sprayer system by using various carbon and nitrogen precursors made of mixtures of benzylamine with toluene, urea...
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Tin‐based nanowire electrodes present desirable properties as lithium‐ion battery anodes, because they undergo volume changes without pulverization. However, they suffer from limited mass loading and propensity for surface parasitic reactions. Herein, we evaluate the electrochemical performances of interconnected nickel‐tin nanowire network electro...
Article
In the critical area of sustainable energy storage, organic batteries are gaining momentum as strong candidates thanks to their lower environmental footprint and great structural versatility. A plethora of organic materials have been proposed and evaluated as both positive and negative electrode materials. Whereas positive electrode chemistries hav...
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The applicability of organic battery materials in conventional rocking-chair lithium (Li)-ion cells remains deeply challenged by the lack of Li-containing and air-stable organic positive electrode chemistries. Decades of experimental and theoretical research in the field has resulted in only a few recent examples of Li-reservoir materials, all of w...
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Hydrogels have reached momentum due to their potential application in a variety of fields including their ability to deliver active molecules upon application of a specific chemical or physical stimulus and to act as easily recyclable catalysts in a green chemistry approach. In this paper, we demonstrate that the same redox-responsive hydrogels bas...
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Lithium-ion batteries are today among the most efficient devices for electrochemical energy storage. However, an improvement of their performance is required to address the challenges of modern grid management, portable technology, and electric mobility. One of the most important limitations to solve is the slow kinetics of redox reactions associat...
Article
In this perspective article, we review some of the most recent advances in the emerging field of organic materials as the electroactive component in solid electrodes for batteries. These comprise, but are not limited to, organometallic salts, small molecular systems, redox-active macromolecules, as well as hybrid formulations with inorganic electro...
Article
Raising the operating potential of the organic positive electrode materials is a crucial challenge if they are to compare with lithium-ion inorganic counterparts. Although many efforts have been directed on tuning through substituent electronic effect, the chemistries than can operate above 3 V vs Li+/Li0, and thus be air stable in the Li-reservoir...
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Mg-ion diffusion in cathodes and dissociation in electrolyte complexes are sluggish processes that hinder the development of Mg batteries. Now, a new design of both the cathode and the electrolyte drastically improves the kinetics of these processes, leading to a high-power Mg battery.
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We report the electrochemistry of a hitherto unexplored Na2MoS4 phase as conversion electrode material for Na‐ and Li‐cation reversible storage. The material adopts an amorphous coordination polymer structure, with mixed Mo and S valences. Ex‐situ XPS and in‐situ XRD analysis reveal a complex interplay between Mo and S redox, while excluding the fo...
Article
This special collection contains a selection of research articles corresponding to contributions presented at Symposium C of the European Materials Science Meeting Edition 2019 that was held in Nice, France, from the 26th to the 31st of May 2019.
Article
1,10‐Phenanthroline‐5,6‐dione (Phendione) ‐ based transition metal complexes are known for their use in pharmacological and catalysis applications. However, their application in electrochemical energy storage has not been investigated thus far. Herein we prove the feasibility of employing phendione ‐ transition metal complexes for electrochemical c...
Preprint
i>1,10-Phenanthroline-5,6-dione (Phendione) - based transition metal complexes are known for their use in pharmacological and catalysis applications. However, their application in electrochemical energy storage has not been investigated thus far. Herein we prove the feasibility of employing phendione - transition metal complexes for electrochemical...
Preprint
Fire-retardant electrolyte chemistries have attracted great attention given their potential to solve the grand challenges of alkali-ion batteries : safety, use of metallic anodes and anodic stability. Whereas extensive analysis and correlations are drawn to explain their unusual electrochemical behaviour, one essential property, their effects on re...
Article
We report on metal assisted chemical etching of Si for the synthesis of mechanically-stable, hybrid crystallographic orientation Si superstructures with high aspect ratio, above 200. This one-pot-type method sustains high etching rates and facilitates reproducible results. The protocol enables the control of the number, angle and location of kinks...
Article
Fire-retardant electrolyte chemistries have attracted great attention given their potential to solve the grand challenges of alkali-ion batteries : safety, use of metallic anodes and anodic stability. Whereas extensive analysis and correlations are drawn to explain their unusual electrochemical behaviour, one essential property, their effects on re...
Article
Vanadium oxides have been extensively investigated as promising electrode materials for alkali ion batteries. Great improvements have been possible by going at nanoscale as well by realizing composites with various carbon allotropes. However, the synthesis methods are not always efficient, nor green, requiring either expensive precursors, extended...
Article
Copper is the conventional, broadly applied anode current collector in lithium-ion batteries, since Li does not form intermetallic alloys with Cu at room temperature. Fast diffusion and trapping of lithium in copper were however suggested in the past and the involved diffusion mechanisms are still not clarified. By using three complementary methods...
Article
There is a proliferation of autonomous microscale devices, which are increasingly in need of power sources of commensurate form factors. The trade-off between the areal energy and power capabilities of miniature energy storage devices restrict their abilities to meet the requirements of these microscale devices. However, three-dimensional (3D) micr...
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Supercapacitor have attracted much attention due to its fast power supply, long cycle life, simple principle, etc. Supercapacitors are widely used in consumer electronics. Activated carbon is a typical material for electric double layer capacitor. Here, we study the electrochemical performance of an activated carbon (TF-B520) bulky paper electrode...
Article
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Small organic materials are generally plagued by their high solubility in battery electrolytes. Finding approaches to suppress the solubilization while not penalizing the gravimetric capacity remains a persisting challenge. Here we propose the concept of Hydrogen-bond stabilized organic battery framework as a viable solution. This is illustrated fo...
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A tri-dimensional interweaving kinked silicon nanowires (k-SiNWs) assembly, with a Ni current collector co-integrated, is evaluated as electrode configuration for lithium ion batteries. The large-scale fabrication of k-SiNWs is based on a procedure for continuous metal assisted chemical etching of Si, supported by a chemical peeling step that enabl...
Article
Electrochemical performances of LiMn2O4 (LMO) – poly (2,2,6,6-tetramethyl-1-piperinidyloxy-4-yl methacrylate) (PTMA) hybrid electrodes are investigated. Different constituent ratios are tested and the impact on the power and the cycling performances is discussed. Variable rate galvanostatic charge/discharge tests show improved energy-power performa...
Article
Water-soluble binders can enable greener and cost effective Li-ion battery manufacturing by eliminating the standard fluorine-based formulations and associated organic solvents. The issue with water-based dispersions, however, remains the difficulty to stabilize them, requiring additional processing complexity. Herein, we show that mechanochemical...
Article
Functional and structural tailoring of three-dimensional (3D) conducting polymer nanoarchitectures is a promising route but remains challenging to develop high-performance electrodes for electrochemical energy storage. Herein, we design poly(3, 4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) 3D mesoporous aerogel electrodes through a si...
Article
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The electrochemistry of poly(2,5-dihydroxyaniline) (PDHA), a novel hybrid molecular configuration with redox active sites and electrical charge conduction along the polymer chain, has been recently reported. The theoretical capacity of this material is estimated at 443 mAh g⁻¹, with high power performances being proposed given the intrinsic electri...
Article
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This paper describes the synthesis and characterization of a new hybrid material based on poly(2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl methacrylate) (PTMA) for lithium battery applications. Our strategy relies on the anchoring of nitroxide-embedding polymer chains onto multi-walled carbon nanotubes (MWCNTs). The resulting hybrid material (MWCNT-g-...
Article
By making use of a semiconducting metal-organic graphene analogue, researchers propose a new generation of supercapacitors with potential as tunable molecular materials for energy.
Article
Flexible portable electronic devices have attracted increasing attention during the last decade. Energy consumption of such devices is ever increasing and performing power sources, that are moreover flexible, need to be developed to seamlessly integrate into such architectures. While lithium-ion batteries appear to be the best solution to meet the...
Article
Full-text available
By using coplanar waveguides, direct access to the dielectric properties of aqueous solutions of polystyrene beads with different diameters from 330 nm to 10 μm is provided. The relative variation of the transmission parameter with respect to water is monitored, ranging from [Formula: see text] obtained for a 9.5% solution with 330 nm diameter bead...
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Energy storage devices that provide high specific power without compromising on specific energy are highly desirable for many electric-powered applications. Here, we demonstrate that polymer organic radical gel materials support fast bulk-redox charge storage, commensurate to surface double layer ion exchange at carbon electrodes. When integrated w...
Article
Research on stimuli responsive polymers builds momentum as nature-inspired applications using man-made materials are increasingly sought. Here, we show for the first time the thermo-responsive upper critical solution temperature (UCST) behaviour of a nitroxide containing polymer based on (2,6,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO). It is demons...
Article
We report a simple and reliable route for the synthesis of three-dimensional bicontinuous Ni–NiO core–shell nanowire networks. The interconnected architecture is self-supported and provides rapid ion and charge collection pathways, as well as efficiently accommodates the volume change induced stress resulting in enhanced lithium storage properties....
Article
Nonlinear second harmonic optical activity of graphene covering a gold photon sieve was determined for different polarizations. The photon sieve consists of a subwavelength gold nanohole array placed on glass. It combines the benefits of efficient light trapping and surface plasmon propagation in order to unravel different elements of graphene seco...
Article
Recently, poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA) has attracted intensive attention for energy storage applications. Organic radical batteries built with this polymer display high power performance. However, the solubility of PTMA in commercial electrolytes shortens the lifespan and the overall performance of the battery. T...
Article
This contribution describes the formation of nanostructured thin film organic radical cathodes. First, the self-assembly of poly(styrene)-block-poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA-b-PS) diblock copolymers is detailed. In order to improve the nano-morphology of the immiscible PTMA and PS domains, the effect of thermal and...
Article
The synthesis of electro-active polymer precursors by single electron transfer-living radical polymerisation (SET-LRP) is demonstrated here. Standard SET-LRP conditions are employed for the controlled polymerisation of 2,2,6,6-tetramethylpiperidin-4-yl methacrylate (TMPM). The controlled behaviour of the polymerisation under these conditions is dem...
Article
Batteries have become fundamental building blocks for the mobility of modern society. Continuous development of novel battery chemistries and electrode materials has nourished progress in building better batteries. Simultaneously, novel device form factors and designs with multi-functional components have been proposed, requiring batteries to not o...
Article
The synthesis and characterisation of novel poly[VDF-g-oligo(EO)] graft copolymers (where VDF and EO stand for vinylidene fluoride and ethylene oxide, respectively) are presented. First, 2-trifluoromethyl oligo(EO) acrylate, MAFTEG, was prepared by esterification of triethylene glycol monomethyl ether (TEG) with 2-trifluoromethacrylic acid (MAF) ca...
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A novel hybrid material displaying a fast and reversible charge storage capability is prepared by electrografting of an alkoxyamine-bearing acrylate onto a carbon nanotubes buckypaper, followed by the quantitative generation of an electroactive polynitroxide.
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Organic redox materials have the potential to radically shift the battery technology landscape. Here, the chemical synthesis of poly(2,5-dihydroxyaniline) with intrinsic electrical conduction and a theoretical energy storage capacity of 443 mAh/g is detailed for the first time. The genuine intramolecular cross-hybridization of quinone redox and pol...
Article
A solvent-free, melt polymerization process of a 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) precursor for rechargeable organic radical batteries is proposed. In situ carbon incorporation in the melted monomer phase yields a nanoscale homogenous polymer composite. Superior battery performances including higher power and cycling stability are attai...
Article
Li-ion battery technology is considered as the most efficient solution for the electrochemical energy storage. While standard liquid electrolyte - based configurations provide best performances, solid state electrolytes are developed as a safer alternative. Herein, we discuss a three step synthesis procedure of self-doped solid block copolymer elec...
Article
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In this contribution we disclose an original strategy towards dense grafting of electrochemically active nitroxide-bearing polymer brushes on multi-walled carbon nanotubes (MWCNTs). Our strategy involves the surface initiated polymerization of 2,2,6,6-tetramethylpiperidin-4-yl methacrylate (TMA) through atom transfer radical polymerization from the...
Article
Surface passivation of silicon anodes is an appealing design strategy for the development of reliable, high capacity lithium-ion batteries. However, the structural stability of the coating layer and its influence on the lithiation process remain largely unclear. Herein, we show that surface coating mediates the swelling dynamics and the fracture pa...
Article
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A simple approach for the production of polymer functionalized graphene nanosheets is reported. The resulting polyacrylonitrile chemisorbed on graphene sheets are made of 1 to 2 layers, with a large majority of graphene single-layers. This novel functionalized graphene exhibits good rate capability as anode in the Li-ion batteries without conductiv...
Article
Solid-state electrolytes are being considered the keystone element for the development of safer all-solid-state lithium-ion batteries. While poly(ethylene oxide) (PEO) solid-state polymer electrolytes are known to support a Li+ flux, satisfying conductivities are reached only above the melting point of the PEO crystallites (>65 [degree]C) rendering...
Article
Despite tremendous effort in designing better Si electrodes based on nanostructured materials, composite and architectures as well as on novel binders and electrolyte additives, sustaining long cycle life at deep lithiation levels is still troublesome[1]. Recent studies have shown that surface coatings can positively impact the cycling stability of...
Article
Li-ion batteries (LIBs) have highest energy density but they suffer from low power density[1]. Energy is stored in LIBs by virtue of reversible Coulombic reactions occurring at both electrodes involving slow charge transfer in the bulk electrode materials and limited diffusion of ions from one electrode to the other. On the other extreme, supercapa...
Article
During the past two decades, many efforts were devoted to increase the performance of Li-ion batteries[1]. Currently, Li-ion technology using carbonate based liquid electrolyte exhibits the best performances but it’s also famous for safety reason: leakages of corrosive products, explosion hazard and narrow stability window. Solid-state electrolytes...
Article
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We detail on a continuous colloidal pattern replication by using contact photolithography. Chrome on quartz masks are fabricated using colloidal nanosphere lithography and subsequently used as photolithography stamps. Hexagonal pattern arrangements with different dimensions (980, 620 and 480 nm, using colloidal particles with respective diameters)...
Article
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High energy and high power electrochemical energy storage devices rely on different fundamental working principles - bulk vs. surface ion diffusion and electron conduction. Meeting both characteristics within a single or a pair of materials has been under intense investigations yet, severely hindered by intrinsic materials limitations. Here, we pro...