Thermal-Switchable, Trifunctional Ceramic-Hydrogel Nanocomposites Enable Full-Lifecycle Security in Practical Battery Systems.

Thermal runaway (TR) failures of large-format lithium-ion battery systems related to fires and explosions have become a growing concern. Here, we design a smart ceramic-hydrogel nanocomposite that provides integrated thermal management, cooling, and fire insulation functionalities and enables full-lifecycle security. The glass-ceramic nanobelt sponges exhibit high mechanical flexibility with 80% reversible compressibility and high fatigue resistance, which can firmly couple with the polymer-nanoparticle hydrogels and form thermal-switchable nanocomposites. In the operating mode, the high enthalpy of the nanocomposites enables efficient thermal management, thereby preventing local temperature spikes and overheating under extremely fast charging conditions. In the case of mechanical or thermal abuse, the stored water can be immediately released, leaving behind a highly flexible ceramic matrix with low thermal conductivity (42 mW m-1 K-1 at 200 °C) and high-temperature resistance (up to 1300 °C), thus effectively cooling the TR battery and alleviating the devastating TR propagation. The versatility, self-adaptivity, environmental friendliness, and manufacturing scalability make this material highly attractive for practical safety assurance applications.

Enhancing strength and ductility via crystalline-amorphous nanoarchitectures in TiZr-based alloys.

Crystalline-amorphous composite have the potential to achieve high strength and high ductility through manipulation of their microstructures. Here, we fabricate a TiZr-based alloy with micrometer-size equiaxed grains that are made up of three-dimensional bicontinuous crystalline-amorphous nanoarchitectures (3D-BCANs). In situ tension and compression tests reveal that the BCANs exhibit enhanced ductility and strain hardening capability compared to both amorphous and crystalline phases, which impart ultra-high yield strength (~1.80 GPa), ultimate tensile strength (~2.3 GPa), and large uniform ductility (~7.0%) into the TiZr-based alloy. Experiments combined with finite element simulations reveal the synergetic deformation mechanisms; i.e., the amorphous phase imposes extra strain hardening to crystalline domains while crystalline domains prevent the premature shear localization in the amorphous phases. These mechanisms endow our material with an effective strength-ductility-strain hardening combination.

Highly compressible and anisotropic lamellar ceramic sponges with superior thermal insulation and acoustic absorption performances.

Advanced ceramic sponge materials with temperature-invariant high compressibility are urgently needed as thermal insulators, energy absorbers, catalyst carriers, and high temperature air filters. However, the application of ceramic sponge materials is severely limited due to their complex preparation process. Here, we present a facile method for large-scale fabrication of highly compressible, temperature resistant SiO2-Al2O3 composite ceramic sponges by blow spinning and subsequent calcination. We successfully produce anisotropic lamellar ceramic sponges with numerous stacked microfiber layers and density as low as 10 mg cm-3. The anisotropic lamellar ceramic sponges exhibit high compression fatigue resistance, strain-independent zero Poisson's ratio, robust fire resistance, temperature-invariant compression resilience from -196 to 1000 °C, and excellent thermal insulation with a thermal conductivity as low as 0.034 W m-1 K-1. In addition, the lamellar structure also endows the ceramic sponges with excellent sound absorption properties, representing a promising alternative to existing thermal insulation and acoustic absorption materials.

Surgical treatment for empyema thoracis: is video-assisted thoracic surgery "better" than thoracotomy?

BACKGROUND: Operations for empyema thoracis are conventionally performed by open thoracotomy, whereas the video-assisted thoracic surgery (VATS) approach remains controversial. This study compares the radiologic and functional outcomes of decortication using the two approaches. METHODS: During a 5-year period, 77 consecutive patients underwent decortication for empyema thoracis at two university teaching hospitals. The choice of surgical approach was decided by surgeon preference. Preoperative and postoperative empyema management was the same in all patients. Postoperative radiologic improvements were graded by a radiologist blinded to the approach used. Functional improvements were assessed by a questionnaire-based survey conducted at a mean of 36 months after the surgical procedure. RESULTS: The VATS approach was used in 41 patients and the thoracotomy approach in 36 patients. Patients in the two groups had similar preoperative demographic and clinical features. No patients required conversion from VATS to thoracotomy or reintervention for empyema. Intraoperative blood loss, duration of chest drain, lengths of hospital stay, and postoperative complication rates were all similar in the two groups. The mean operation time in the VATS group was significantly shorter (2.5 versus 3.8 hours, p < 0.001). Decortication using both approaches gave similar degrees of postoperative radiologic and functional improvements. Of the 42 patients available for follow-up, the 21 who received the VATS approach reported significantly less postoperative pain (p = 0.04), greater satisfaction with the wounds (p < 0.0001), and greater satisfaction with the operation overall (p = 0.006). CONCLUSIONS: VATS allows equally effective decortication for empyema as thoracotomy. However, the VATS approach gives less pain and greater patient acceptance.