Easy Diameter Tuning of Silicon Nanowires with Low-Cost SnO2-Catalyzed Growth for Lithium-Ion Batteries.

Silicon nanowires are appealing structures to enhance the capacity of anodes in lithium-ion batteries. However, to attain industrial relevance, their synthesis requires a reduced cost. An important part of the cost is devoted to the silicon growth catalyst, usually gold. Here, we replace gold with tin, introduced as low-cost tin oxide nanoparticles, to produce a graphite-silicon nanowire composite as a long-standing anode active material. It is equally important to control the silicon size, as this determines the rate of decay of the anode performance. In this work, we demonstrate how to control the silicon nanowire diameter from 10 to 40 nm by optimizing growth parameters such as the tin loading and the atmosphere in the growth reactor. The best composites, with a rich content of Si close to 30% wt., show a remarkably high initial Coulombic efficiency of 82% for SiNWs 37 nm in diameter.

Effect of Size and Shape on Electrochemical Performance of Nano-Silicon-Based Lithium Battery.

Silicon is a promising material for high-energy anode materials for the next generation of lithium-ion batteries. The gain in specific capacity depends highly on the quality of the Si dispersion and on the size and shape of the nano-silicon. The aim of this study is to investigate the impact of the size/shape of Si on the electrochemical performance of conventional Li-ion batteries. The scalable synthesis processes of both nanoparticles and nanowires in the 10-100 nm size range are discussed. In cycling lithium batteries, the initial specific capacity is significantly higher for nanoparticles than for nanowires. We demonstrate a linear correlation of the first Coulombic efficiency with the specific area of the Si materials. In long-term cycling tests, the electrochemical performance of the nanoparticles fades faster due to an increased internal resistance, whereas the smallest nanowires show an impressive cycling stability. Finally, the reversibility of the electrochemical processes is found to be highly dependent on the size/shape of the Si particles and its impact on lithiation depth, formation of crystalline Li15Si4 in cycling, and Li transport pathways.

A Scalable Silicon Nanowires-Grown-On-Graphite Composite for High-Energy Lithium Batteries.

Silicon (Si) is the most promising anode candidate for the next generation of lithium-ion batteries but difficult to cycle due to its poor electronic conductivity and large volume change during cycling. Nanostructured Si-based materials allow high loading and cycling stability but remain a challenge for process and engineering. We prepare a Si nanowires-grown-on-graphite one-pot composite (Gt-SiNW) via a simple and scalable route. The uniform distribution of SiNW and the graphite flakes alignment prevent electrode pulverization and accommodate volume expansion during cycling, resulting in very low electrode swelling. Our designed nanoarchitecture delivers outstanding electrochemical performance with a capacity retention of 87% after 250 cycles at 2C rate with an industrial electrode density of 1.6 g cm-3. Full cells with NMC-622 cathode display a capacity retention of 70% over 300 cycles. This work provides insights into the fruitful engineering of active composites at the nano- and microscales to design efficient Si-rich anodes.

Migratory foreign body of neck in a battered baby: a case report.

Only a small number of ingested foreign bodies perforate the esophagus and even smaller fraction migrate extramucosally with no symptoms. Both of these events are even rarer after marble ingestion. We report here a case of battered baby with homicidal marble ingestion which perforated the esophagus and migrated into the soft tissue of neck. It was diagnosed after 21 days asymptomatic period. The foreign body migrated into the tracheo-esophageal groove, lying deep to strap muscles, which was removed by neck exploration.

Thyroid gland in carcinoma of the larynx and hypopharynx: analysis of factors indicating thyroidectomy.

BACKGROUND: This prospective study analyzed the factors that could predict thyroid gland involvement in patients suffering from malignancy of the larynx and laryngopharynx. METHODS: Fifty patients underwent total laryngectomy with either ipsilateral hemithyroidectomy or total thyroidectomy in cases with subglottic extent more than 1.5 cm or in patients undergoing total laryngopharyngectomy for hypopharyngeal malignancy. The laryngectomy specimen and thyroid specimen were studied histologically with multiple serial sections. RESULTS: The majority of patients had glottic involvement followed by supraglottic and hypopharyngeal lesions. The thyroid gland was found to be enlarged and nodular in six patients. One of six patients had frank induration with gross extralaryngeal spread. Our study showed a 2% incidence of thyroid gland invasion by tumour. CONCLUSIONS: The presence of subglottic extension of more than 2 cm, cricoid cartilage invasion, and perithyroidal soft tissue involvement can be considered indicators for sacrificing the whole thyroid gland during surgery.

Epithelioid hemangioendothelioma of middle ear masquerading as glomus tumor.

Hemangioendothelioma is still one of the less-known tumors of vascular origin. The authors report the case of a 38-year-old man who presented with unilateral, nonpulsatile timnitus, aural fullness, and a sense of imbalance. Imaging showed a contrast enhancing soft tissue mass lesion involving the external auditory canal and middle ear, mimicking as glomus tumor. Histopathological examination of surgical specimen showed it to be hemagioendothelioma.