The method we introduced in 1992 for measuring hardness and elastic modulus by instrumented indentation techniques has widely been adopted and used in the characterization of small-scale mechanical behavior. Since its original development, the method has undergone numerous refinements and changes brought about by improvements to testing equipment and techniques as well as from advances in our understanding of the mechanics of elastic–plastic contact. Here, we review our current understanding of the mechanics governing elastic–plastic indentation as they pertain to load and depth-sensing indentation testing of monolithic materials and provide an update of how we now implement the method to make the most accurate mechanical property measurements. The limitations of the method are also discussed.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0884291400085800

Measurement of hardness and elastic modulus by instrumented indentation: Advances in understanding and refinements to methodology

Li-ion battery materials: present and future

The lithium metal battery is strongly considered to be one of the most promising candidates for high-energy-density energy storage devices in our modern and technology-based society. However, uncontrollable lithium dendrite growth induces poor cycling efficiency and severe safety concerns, dragging lithium metal batteries out of practical applications. This review presents a comprehensive overview of the lithium metal anode and its dendritic lithium growth. First, the working principles and technical challenges of a lithium metal anode are underscored. Specific attention is paid to the mechanistic understandings and quantitative models for solid electrolyte interphase (SEI) formation, lithium dendrite nucleation, and growth. On the basis of previous theoretical understanding and analysis, recently proposed strategies to suppress dendrite growth of lithium metal anode and some other metal anodes are reviewed. A section dedicated to the potential of full-cell lithium metal batteries for practical applicatio...

Toward Safe Lithium Metal Anode in Rechargeable Batteries: A Review.

Graphene has attracted tremendous research interest in recent years, owing to its exceptional properties. The scaled-up and reliable production of graphene derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO), offers a wide range of possibilities to synthesize graphene-based functional materials for various applications. This critical review presents and discusses the current development of graphene-based composites. After introduction of the synthesis methods for graphene and its derivatives as well as their properties, we focus on the description of various methods to synthesize graphene-based composites, especially those with functional polymers and inorganic nanostructures. Particular emphasis is placed on strategies for the optimization of composite properties. Lastly, the advantages of graphene-based composites in applications such as the Li-ion batteries, supercapacitors, fuel cells, photovoltaic devices, photocatalysis, as well as Raman enhancement are described (279 references).

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Graphene-based composites

A review of shape memory alloy research, applications and opportunities

Since the initial report on the epitaxial growth of α-Fe films on hydrogen-terminated Si(111) surfaces at 300 K, two in-plane orientation relationships, twinned and aligned epitaxy, have been suggested. In this paper, the epitaxial growth of Fe on Si(111) is further examined in detail by x-ray-diffraction θ-2θ scans, x-ray-diffraction O scans, transmission electron microscopy, and reflection high-energy electron diffraction. Twinned epitaxy at the Fe/Si interface is established, i.e., (111) α-Fe ∥(111) Si and [110] α-Fe ∥[110] Si . As the film thickness increases, the formation of twins in the epitaxial α-Fe films is observed. The apparent «aligned epitaxy» is the result of twinning in the α-Fe film

Formation of twins during epitaxial growth of alpha -iron films on silicon (111).

Polyvinylidene fluoride (PVDF) is the most popular binder in commercial lithium-ion batteries, but is incompatible with a silicon (Sdi) anode because the PVDF fails to maintain the mechanical integrity of the Si electrode upon cycling. Herein, an alucone coating synthesized by molecular-layer deposition has been applied on the laminated electrode fabricated with PVDF to systematically study the sole impact of the surface modification on the electrochemical and mechanical properties of the Si electrode, without the interference of other functional polymer binders. The enhanced mechanical properties of the coated electrodes, confirmed by mechanical characterization, can help accommodate the repeated volume fluctuations, preserve the electrode structure during electrochemical reactions, and thereby, leading to a remarkably improvement of electrochemical performance. Due to the alucone coating, the Si electrodes achieve highly reversible cycling performance with a specific capacity of 1,490 mAh g-1 (0.90 mAh ...

Systematic Investigation of the Alucone-Coating Enhancement on Silicon Anodes

Nonstoichiometry and Li-ion transport in lithium zirconate: The role of oxygen vacancies

The interaction of a friction modifier and a calcium phenate detergent additive, with zinc dialkyl dithiophosphates (ZDDPs) in the formation of antiwear films on A383, has been studied using synchrotron radiation and nanoindentation techniques. X-ray absorption near edge structure (XANES) spectroscopy has shown that films prepared from oils containing both ZDDP and detergent, and ZDDP and molybdenum dithiocarbamate (MoDTC), are chemically similar to, but thicker than those made from oils containing only ZDDP. In addition, wear was greatly reduced in the presence of the detergent which was correlated with the basicity and the presence of the friction modifier. The phosphorus K and L edge XANES spectra show that the tribofilms are polyphosphate glasses of similar nature to those found on steel, but characterised by a shorter chain length. The sulphur K edge shows a MoS2 like film and under certain conditions, the presence of a sulphate species is detected. High resolution topographic images and mech...

Nanoscale chemistry and mechanical properties of tribofilms on Al–Si alloy (A383): interaction of ZDDP, calcium detergent and molybdenum friction modifier

The electrochemical quartz crystal microbalance (QCMB) was applied to the study of amorphous La-Ni thin film electrodes Amorphous LaNi 5 thin films were deposited on both AT and BT cut quartz crystal substrates by physical vapor deposition in ultrahigh vacuum The electrochemical QCMB measurements determine the mass loading of hydrogen atoms (H) as well as the stress in the film upon H insertion These experiments also allow in situ monitoring of hydrogen absorption-desorption and oxidation-reduction reactions in metal hydride thin film electrodes

Yang-Tse Cheng

Papers

Formation of twins during epitaxial growth of alpha -iron films on silicon (111).

Systematic Investigation of the Alucone-Coating Enhancement on Silicon Anodes

Nonstoichiometry and Li-ion transport in lithium zirconate: The role of oxygen vacancies

Nanoscale chemistry and mechanical properties of tribofilms on Al–Si alloy (A383): interaction of ZDDP, calcium detergent and molybdenum friction modifier

Studies of Metal Hydride Electrodes Using an Electrochemical Quartz Crystal Microbalance