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Marnix Wagemaker

Bio: Marnix Wagemaker is an academic researcher from Delft University of Technology. The author has contributed to research in topics: Electrolyte & Lithium. The author has an hindex of 50, co-authored 143 publications receiving 8243 citations. Previous affiliations of Marnix Wagemaker include Radboud University Nijmegen & Northwestern University.


Papers
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Journal ArticleDOI
TL;DR: The particle size dependence of insertion reactions has been investigated for lithiated anatase TiO2, revealing progressively increasing Li capacity and Li-ion solubility for decreasing particle sizes, strongly deviating from the expected Li-rich andLi-poor phase separation as occurs in the bulk material.
Abstract: Insertion reactions are of key importance for Li ion and hydrogen storage materials and energy storage devices. The particle size dependence of insertion reactions has been investigated for lithiated anatase TiO2, revealing progressively increasing Li capacity and Li-ion solubility for decreasing particle sizes, strongly deviating from the expected Li-rich and Li-poor phase separation as occurs in the bulk material. The phase diagram alters significantly, changing the materials properties already at sizes as large as 40 nm. A rationale is found in the surface strain that occurs between the different intercalated phases, which becomes energetically too costly in small particles. In particular the observed particle size-induced solid solution behavior is expected to have fundamental and practical implications for two-phase lithium or hydrogen insertion reactions.

682 citations

Journal ArticleDOI
25 Jul 2002-Nature
TL;DR: The direct observation by solid-state nuclear magnetic resonance of the continuous lithium-ion exchange between the intermixed crystallographic phases of lithium-intercalated TiO2 is reported, finding that, at room temperature, the continuous flux of lithium ions across the phase boundaries is as high as 1.2 × 1020 s-1 m-2.
Abstract: Microcrystalline TiO2 with an anatase crystal structure is used as an anode material for lithium rechargeable batteries1,2, and also as a material for electrochromic3,4,5,6 and solar-cell devices7,8. When intercalated with lithium, as required for battery applications, TiO2 anatase undergoes spontaneous phase separation into lithium-poor (Li0.01TiO2) and lithium-rich (Li0.6TiO2) domains on a scale of several tens of nanometres9. During discharge, batteries need to maintain a constant electrical potential between their electrodes over a range of lithium concentrations. The two-phase equilibrium system in the electrodes provides such a plateau in potential, as only the relative phase fractions vary on charging (or discharging) of the lithium. Just as the equilibrium between a liquid and a vapour is maintained by a continuous exchange of particles between the two phases, a similar exchange is required to maintain equilibrium in the solid state. But the time and length scales over which this exchange takes place are unclear. Here we report the direct observation by solid-state nuclear magnetic resonance of the continuous lithium-ion exchange between the intermixed crystallographic phases of lithium-intercalated TiO2. We find that, at room temperature, the continuous flux of lithium ions across the phase boundaries is as high as 1.2 × 1020 s-1 m-2.

449 citations

Journal ArticleDOI
06 Nov 2020-Science
TL;DR: The “cationic potential” is introduced that captures the key interactions of layered materials and makes it possible to predict the stacking structures and is demonstrated through the rational design and preparation of layered electrode materials with improved performance.
Abstract: Sodium-ion batteries have captured widespread attention for grid-scale energy storage owing to the natural abundance of sodium. The performance of such batteries is limited by available electrode materials, especially for sodium-ion layered oxides, motivating the exploration of high compositional diversity. How the composition determines the structural chemistry is decisive for the electrochemical performance but very challenging to predict, especially for complex compositions. We introduce the "cationic potential" that captures the key interactions of layered materials and makes it possible to predict the stacking structures. This is demonstrated through the rational design and preparation of layered electrode materials with improved performance. As the stacking structure determines the functional properties, this methodology offers a solution toward the design of alkali metal layered oxides.

444 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the nanosized Li4+xTi5O12 spinel by electrochemical discharging and neutron diffraction, and the unique zero-strain property of the spinel implies a different origin of the curved voltage profiles observed for its nosized crystallites.
Abstract: The nanosized Li4+xTi5O12 spinel is investigated by electrochemical (dis)charging and neutron diffraction. The near-surface environment of the nanosized particles allows higher Li ion occupancies, leading to a larger storage capacity. However, too high surface lithium storage leads to irreversible capacity loss, most likely due to surface reconstruction or mechanical failure. A mechanism where the large near-surface capacity ultimately leads to surface reconstruction rationalizes the existence of an optimal particle size. Recent literature attributes the curved voltage profiles, leading to a reduced length of the voltage plateau, of nanosized electrode particles to strain and interface energy from the coexisting end members. However, the unique zero-strain property of the Li4+xTi5O12 spinel implies a different origin of the curved voltage profiles observed for its nanosized crystallites. It is proposed to be the consequence of different structural environments in the near-surface region, depending on the ...

374 citations

Journal ArticleDOI
TL;DR: In situ/operando characterization techniques provide information on the structure evolution, redox mechanism, solid-electrolyte interphase (SEI) formation, side reactions, and Li-ion transport properties under operating conditions under realistic operation conditions.
Abstract: The increasing demands of energy storage require the significant improvement of current Li-ion battery electrode materials and the development of advanced electrode materials. Thus, it is necessary to gain an in-depth understanding of the reaction processes, degradation mechanism, and thermal decomposition mechanisms under realistic operation conditions. This understanding can be obtained by in situ/operando characterization techniques, which provide information on the structure evolution, redox mechanism, solid-electrolyte interphase (SEI) formation, side reactions, and Li-ion transport properties under operating conditions. Here, the recent developments in the in situ/operando techniques employed for the investigation of the structural stability, dynamic properties, chemical environment changes, and morphological evolution are described and summarized. The experimental approaches reviewed here include X-ray, electron, neutron, optical, and scanning probes. The experimental methods and operating principles, especially the in situ cell designs, are described in detail. Representative studies of the in situ/operando techniques are summarized, and finally the major current challenges and future opportunities are discussed. Several important battery challenges are likely to benefit from these in situ/operando techniques, including the inhomogeneous reactions of high-energy-density cathodes, the development of safe and reversible Li metal plating, and the development of stable SEI.

345 citations


Cited by
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01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

29,323 citations

Journal ArticleDOI
TL;DR: In this article, a review of the key technological developments and scientific challenges for a broad range of Li-ion battery electrodes is presented, and the potential/capacity plots are used to compare many families of suitable materials.

5,057 citations

Journal ArticleDOI
TL;DR: This critical review of the current status of hydrogen storage within microporous metal-organic frameworks provides an overview of the relationships between structural features and the enthalpy of hydrogen adsorption, spectroscopic methods for probing framework-H(2) interactions, and strategies for improving storage capacity.
Abstract: New materials capable of storing hydrogen at high gravimetric and volumetric densities are required if hydrogen is to be widely employed as a clean alternative to hydrocarbon fuels in cars and other mobile applications. With exceptionally high surface areas and chemically-tunable structures, microporous metal–organic frameworks have recently emerged as some of the most promising candidate materials. In this critical review we provide an overview of the current status of hydrogen storage within such compounds. Particular emphasis is given to the relationships between structural features and the enthalpy of hydrogen adsorption, spectroscopic methods for probing framework–H2 interactions, and strategies for improving storage capacity (188 references).

4,511 citations

Journal ArticleDOI
TL;DR: In this paper, the capacitive effects of nanostructured materials for electrochemical energy storage have been investigated over a dimensional regime where both capacitive and lithium intercalation processes contribute to the total stored charge.
Abstract: The advantages in using nanostructured materials for electrochemical energy storage have largely focused on the benefits associated with short path lengths. In this paper, we consider another contribution, that of the capacitive effects, which become increasingly important at nanoscale dimensions. Nanocrystalline TiO2 (anatase) was studied over a dimensional regime where both capacitive and lithium intercalation processes contribute to the total stored charge. An analysis of the voltammetric sweep data was used to distinguish between the amount of charge stored by these two processes. At particle sizes below 10 nm, capacitive contributions became increasingly important, leading to greater amounts of total stored charge (gravimetrically normalized) with decreasing TiO2 particle size. The area normalized capacitance was determined to be well above 100 μF/cm2, confirming that the capacitive contribution was pseudocapacitive in nature. Moreover, reducing the particle size to the nanoscale regime led to faster...

3,572 citations