Herein we report on a general approach to delaminate multi-layered MXenes using an organic base to induce swelling that in turn weakens the bonds between the MX layers. Simple agitation or mild sonication of the swollen MXene in water resulted in the large-scale delamination of the MXene layers. The delamination method is demonstrated for vanadium carbide and titanium carbonitride MXenes.

Collection-based institutions-zoos, aquariums, museums, and botanical gardens-exhibit wildlifeand thus have a special connection with nature. Many of these institutions emphasize a mission of conservation, and, undeniably, they do contribute directly to conservation education and conservation science. They present an exceptional opportunity for many urban residents to see the wonders of life, and they can contribute to education and habitat preservation. Because many collection-based institutions now hold a stated mission of conservation, we suggest eight potential questions to evaluate actions toward that mission: (1) Does conservation thought define policy decisions? (2) Is there sufficient organizational funding for conservation activities?(3) Is there a functional conservation department? (4) Does the institution advocate for conservation? (5) Do conservation education programs effectively target children and adults? (6) Does the institution contribute directly to habitat protection locally and internationally? (7) Do exhibits explain and promote conservation efforts? and (8) Do internal policies and activities protect the environment? These questions are offered as a place to begin discussion. We hope they will help employees and administrators of a collection-based institution (and citizens of the surrounding community) think about and support their institution's conservation activities. Public support and praise for institutions that are striving toward solutions for conservation problems and pressure on organizations that are moving more slowly toward a conservation orientation can help shift more resources toward saving nature. Evaluación de la Misión de Conservación de Zoológicos, Acuarios, Jardines Botánicos o Museos de Historia NaturalResumen: Las instituciones basadas en colecciones (zoológicos, acuarios, museos y jardines botánicos) exhiben vida silvestre. Por lo tanto, tienen una conexión especial con la naturaleza. Muchas de estas instituciones destacan una misión de conservación y, sin duda contribuyen directamente a la educación y la ciencia de la conservación. Brindan una oportunidad excepcional para que muchos residentes urbanos vean las maravillas de la vida, y pueden contribuir a la educación y a la preservación del hábitat. Debido a que en la actualidad muchas de las instituciones basadas en colecciones tienen una misión de conservación manifiesta, sugerimos ocho preguntas potenciales para evaluar las acciones hacia el cumplimiento de esa misión: (1) ¿Las consideraciones sobre la conservación definen las decisiones sobre políticas? (2) ¿Hay suficiente financiamiento organizacional para las actividades de conservación? (3) ¿Hay un departamento de conservación que funcione? (4) ¿La institución aboga por la conservación? (5) ¿Los programas de educación en conservación se ‡ Miller et al. Conservation and Collection-Based Institutions 87enfocan eficientemente sobre niños y adultos? (6) ¿La institución contribuye directamente a la conservación del hábitat a nivel local e internacional? (7) ¿Las e...

Addition of dispersants to aqueous based lithium-ion battery electrode formulations containing LiFePO(4) is critical to obtaining a stable suspension. The resulting colloidal suspensions enable dramatically improved coating deposition when processing electrodes. This research examines the colloidal chemistry modifications based on polyethyleneimine (PEI) addition and dispersion characterization required to produce high quality electrode formulations and coatings for LiFePO(4) active cathode material. The isoelectric point, a key parameter in characterizing colloidal dispersion stability, of LiFePO(4) and super P C45 were determined to be pH = 4.3 and 3.4, respectively. PEI, a cationic surfactant, was found to be an effective dispersant. It is demonstrated that 1.0 wt % and 0.5 wt % PEI were required to stabilize the LiFePO(4) and super P C45 suspension, respectively. LiFePO(4) cathode suspensions with 1.5 wt % PEI demonstrated the best dispersibility of all components, as evidenced by viscosity and agglomerate size of the suspensions and elemental distribution within dry cathodes. The addition of PEI significantly improved the LiFePO(4) performance.

Switching manufacturing of composite battery electrodes from an organic system to an aqueous system provides both economic and environmental advantages. However, particle agglomeration of the electrode components and poor wetting of electrode dispersions to the current collectors are inherently introduced. Particle agglomeration can be mitigated by selection of appropriate dispersants. This research examines the effect of dispersant, poly(ethyleneimine) (PEI), on the associated morphology and electrochemical performance of LiFePO 4. The addition of PEI reduces the agglomerate size and contributes to a more homogeneous distribution of cathode constituents, which results in a smoother, more uniform cathode surface. The LiFePO 4 cathodes with PEI demonstrated a higher Li + diffusion coefficient (1 × 10 −14 cm 2 s −1), better initial capacity (>142 mAh g −1), greater capacity retention (∼100%), and superior rate performance compared to the cathodes without PEI. When PEI concentration was varied, the LiFePO 4 cathode with 2 wt% PEI exhibited the best performance at 167 mAh g −1 capacity (98% of the theoretical capacity) and 100% retention after 50 cycles when discharged at 0.2C at 25 • C in a half cell.

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We demonstrate a shear thickening electrolyte that stiffens into a solid-like barrier during a high energy event, like a car crash. This barrier prevents the electrodes from shorting during an impact, reducing the risk of fire or catastrophic safety events. In addition, we have demonstrated the ability to cycle NMC/graphite lithium ion cells over 200 cycles with no loss of capacity after formation. This chemistry introduces multifunctionality to a material previously feared due to its flammability.

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Tape-cast pseudo-cubic zirconia pellets were surface irradiated by two coherent interfering high-power short-pulse Nd:YAG laser beams. The interfering beams of the third harmonic with a wavelength of 355 nm of a 2.5-ns Q-switched laser produced a line-like intensity distribution with a periodic distance of 3.3 lm due to the selected angle between the beams. The resulting nonuniform surface heating produced a microstructure consisting of ultrafine-grained zirconia with a grain size of about 10 nm within the top 100-200 nm depth of the treated surface region due to the high cooling rates during short-pulse laser processing (up to 10 10 K/s). The surface morphology closely followed the microperiodic heat treatment provided by the interfering laser beams. The pore size distribution within the periodic surface morphology ranged from a few nanometers to a maximum of half of the periodic line distances.