observation of the electrochemical lithiation of a single MnO@C nanorod electrode with core/shell structure.

Transition metal oxides (TMOs) play a crucial role in lithium-ion batteries (LIBs) due to their high theoretical capacity, natural abundance, and benign environmental impact, but they suffer from limitations such as cyclability and high-rate discharge ability. One leading cause is the lithiation-induced volume expansion (LIVE) for "conversion"-type TMOs, which can result in high stress, fracture and pulverization. Using carbon layers is an effective strategy to provide effective volumetric accommodation for lithium-ion (Li) insertion; however, the detailed mechanism is unknown.

In situ observation of cracking and self-healing of solid electrolyte interphases during lithium deposition.

The growth of lithium (Li) whiskers is detrimental to Li batteries. However, it remains a challenge to directly track Li whisker growth. Here we report in situ observations of electrochemically induced Li deposition under a CO atmosphere inside an environmental transmission electron microscope.

In situ imaging electrocatalytic CO reduction and evolution reactions in all-solid-state Li-CO nanobatteries.

Li-CO batteries are promising energy storage devices owing to their high energy density and possible applications for CO capture. However, still some critical issues, such as high charging overpotential and poor cycling stability caused by the sluggish decomposition of LiCO discharge products, need to be addressed before the practical applications of Li-CO batteries. Exploring highly efficient catalysts and understanding their catalytic mechanisms for the CO reduction reaction (CORR) and evolution reaction (COER) are critical for the application of Li-CO batteries.

A 2.9 GPa Strength Nano-Grained and Nano-Precipitated 304L-Type Austenitic Stainless Steel.

Austenitic stainless steel has high potential as nuclear and engineering materials, but it is often coarse grained and has relatively low yield strength, typically 200-400 MPa. We prepared a bulk nanocrystalline lanthanum-doped 304L austenitic stainless steel alloy by a novel technique that combines mechanical alloying and high-pressure sintering. The achieved alloy has an average grain size of 30 ± 12 nm and contains a high density (~10 m) of lanthanum-enriched nanoprecipitates with an average particle size of approx.

Electrochemical Study of Na-O/CO Batteries in an Environmental Transmission Electron Microscope.

Metal-air batteries are potential candidates for post-lithium energy storage devices due to their high theoretical energy densities. However, our understanding of the electrochemistry of metal-air batteries is still in its infancy. Herein we report studies of Na-O/CO (O and CO mixture) and Na-O batteries with either carbon nanotubes (CNTs) or Ag nanowires as the air cathode medium in an advanced aberration corrected environmental transmission electron microscope.

Lithium whisker growth and stress generation in an in situ atomic force microscope-environmental transmission electron microscope set-up.

Lithium metal is considered the ultimate anode material for future rechargeable batteries, but the development of Li metal-based rechargeable batteries has achieved only limited success due to uncontrollable Li dendrite growth. In a broad class of all-solid-state Li batteries, one approach to suppress Li dendrite growth has been the use of mechanically stiff solid electrolytes. However, Li dendrites still grow through them.

Turbostratic carbon-localised FeS nanocrystals as anodes for high-performance sodium-ion batteries.

Low-cost metal sulfides are promising anode materials for sodium-ion batteries (SIBs); however, they suffer from sluggish kinetics and large volume expansion upon cycling. Here, a strategy to grow FeS on turbostratic carbon (t-carbon) assisted by chemical interactions between Fe and C electrons was realized via a simple and scalable mechanical alloying (MA) approach with a trace amount of CNTs. The structural change in CNTs synchronized with the in situ growth of FeS on the transformed t-carbon during the MA process, forming localised FeS nanocrystals wrapped in the frameworks of t-carbon.

Ultrastrong nanocrystalline steel with exceptional thermal stability and radiation tolerance.

Nanocrystalline (NC) metals are stronger and more radiation-tolerant than their coarse-grained (CG) counterparts, but they often suffer from poor thermal stability as nanograins coarsen significantly when heated to 0.3 to 0.5 of their melting temperature (T).

Radiation tolerance of La-doped nanocrystalline steel under heavy-ion irradiation at different temperatures.

Nanostructured materials have great potential for use as structural materials in advanced nuclear reactors due to the high density of grain boundaries that can serve as sinks to absorb irradiation-induced defects. In the present study, the irradiation tolerance of a La-doped nanocrystalline 304 austenitic stainless steel (NC-La) with a grain size of about 40 nm was investigated under an irradiation of 6 MeV Au ions to 1.5 × 10 ions cm at 600 °C and room temperature.

Air-Stable Lithium Spheres Produced by Electrochemical Plating.

Lithium metal is an ideal anode for next-generation lithium batteries owing to its very high theoretical specific capacity of 3860 mAh g but very reactive upon exposure to ambient air, rendering it difficult to handle and transport. Air-stable lithium spheres (ASLSs) were produced by electrochemical plating under CO atmosphere inside an advanced aberration-corrected environmental transmission electron microscope. The ASLSs exhibit a core-shell structure with a Li core and a Li CO shell.

In Situ Imaging the Oxygen Reduction Reactions of Solid State Na-O Batteries with CuO Nanowires as the Air Cathode.

We report real time imaging of the oxygen reduction reactions (ORRs) in all solid state sodium oxygen batteries (SOBs) with CuO nanowires (NWs) as the air cathode in an aberration-corrected environmental transmission electron microscope under an oxygen environment. The ORR occurred in a distinct two-step reaction, namely, a first conversion reaction followed by a second multiple ORR. In the former, CuO was first converted to CuO and then to Cu; in the latter, NaO formed first, followed by its disproportionation to NaO and O.

Ceramic nanowelding.

Ceramics possess high temperature resistance, extreme hardness, high chemical inertness and a lower density compared to metals, but there is currently no technology that can produce satisfactory joints in ceramic parts and preserve the excellent properties of the material. The lack of suitable joining techniques for ceramics is thus a major road block for their wider applications. Herein we report a technology to weld ceramic nanowires, with the mechanical strength of the weld stronger than that of the pristine nanowires.

A quenchable superhard carbon phase synthesized by cold compression of carbon nanotubes.

A quenchable superhard high-pressure carbon phase was synthesized by cold compression of carbon nanotubes. Carbon nanotubes were placed in a diamond anvil cell, and x-ray diffraction measurements were conducted to pressures of approximately 100 GPa. A hexagonal carbon phase was formed at approximately 75 GPa and preserved at room conditions.