RESUMEN
Graphitized carbon materials from biomass resources were successfully synthesized with an iron catalyst, and their electrochemical performance as anode materials for lithium-ion batteries (LIBs) was investigated. Peak pyrolysis temperatures between 850 and 2000 °C were covered to study the effect of crystallinity and microstructural parameters on the anodic behavior, with a focus on the first-cycle Coulombic efficiency, reversible specific capacity, and rate performance. In terms of capacity, results at the highest temperatures are comparable to those of commercially used synthetic graphite derived from a petroleum coke precursor at higher temperatures, and up to twice as much as that of uncatalyzed biomass-derived carbons. The opportunity to graphitize low-cost biomass resources at moderate temperatures through this one-step environmentally friendly process, and the positive effects on the specific capacity, make it interesting to develop more sustainable graphite-based anodes for LIBs.
RESUMEN
Batteries based on cathode materials that operate at high cathode potentials, such as LiNi0.5 Mn1.5 O4 (LNMO), in lithium-ion batteries or graphitic carbons in dual-ion batteries suffer from anodic dissolution of the aluminum (Al) current collector in organic solvent-based electrolytes based on imide salts, such as lithium bis(trifluoromethanesulfonyl) imide (LiTFSI). In this work, we developed a protective surface modification for the Al current collector by applying ceramic coatings of chromium nitride (Crx N) and studied the anodic Al dissolution behavior. By magnetron sputter deposition, two different coating types, which differ in their composition according to the CrN and Cr2 N phases, were prepared and characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and their electronic conductivity. Furthermore, the anodic dissolution behavior was studied by cyclic voltammetry and chronocoulometry measurements in two different electrolyte mixtures, that is, LiTFSI in ethyl methyl sulfone and LiTFSI in ethylene carbonate/dimethyl carbonate 1:1 (by weight). These measurements showed a remarkably reduced current density or cumulative charge during the charge process, indicating an improved anodic stability of the protected Al current collector. The coating surfaces after electrochemical treatment were characterized by means of SEM and XPS, and the presence or lack of pit formation, as well as electrolyte degradation products could be well correlated to the electrochemical results.
RESUMEN
Ectopia cordis (EC) is characterized by a complete or partial malposition of the heart outside the thorax. Despite the interdisciplinary treatment, the repair of EC is still very difficult and offers new surgical challenges because of its complexity and various combinations with other anomalies. We report the successful outcome after using a pedicled latissimus dorsi flap in reconstructive surgery in the setting of chronic wound dehiscence in an 8-month-old female infant born with a thoracic EC and omphalocele.
RESUMEN
PURPOSE: Stabilization and replacement of ribs is still a challenge, because most available systems for intramedullary and extramedullary fixation are less than perfect. We present our experience with a modified device, which compensates for several disadvantages in other methods. DESCRIPTION: Originating from the Strasbourg Thoracic Osteosyntheses System (STRATOS [MedXpert GmbH, Heitersheim, Germany]), the multidirectional thoracic wall stabilization system uses tripodal clips with sharp clasping legs. They can be placed without dissecting the ribs, and bridge fractures or defects with titanium bars can be avoided. A rotating lug provides multidirectional stabilization. EVALUATION: We used the multidirectional thoracic wall stabilization system in 4 patients (thoracic deformity, Poland syndrome, flail chest, and thoracic wall hernia). Placement of the devices met with expectations on simplified handling. The long-term follow-up showed no displacement or fracture of the implants and an uncomplicated clinical course. CONCLUSIONS: The newly designed multidirectional thoracic wall stabilization system provides multidirectional use and reduces surgical trauma. In the long term, this device could help to lower the threshold for surgical stabilization of flail chest, for example, and widens the spectrum of less-invasive reconstruction of chest wall deformities.
