Carbon-coated honeycomb Ni-Mn-Co-O inverse opal: a high capacity ternary transition metal oxide anode for Li-ion batteries

We present the formation of a carbon-coated honeycomb ternary Ni-Mn-Co-O inverse opal as a conversion mode anode material for Li-ion battery applications. In order to obtain high capacity via conversion mode reactions, a single phase crystalline honeycombed IO structure of Ni-Mn-Co-O material was first formed. This Ni-Mn-Co-O IO converts via reversible redox reactions and Li2O formation to a 3D structured matrix assembly of nanoparticles of three (MnO, CoO and NiO) oxides, that facilitates efficient reactions with Li. A carbon coating maintains the structure without clogging the open-worked IO pore morphology for electrolyte penetration and mass transport of products during cycling. The highly porous IO was compared in a Li-ion half-cell to nanoparticles of the same material and showed significant improvement in specific capacity and capacity retention. Further optimization of the system was investigated by incorporating a vinylene carbonate additive into the electrolyte solution which boosted performance, offering promising high-rate performance and good capacity retention over extended cycling. The analysis confirms the possibility of creating a ternary transition metal oxide material with binder free accessible open-worked structure to allow three conversion mode oxides to efficiently cycle as an anode material for Li-ion battery applications

2D and 3D photonic crystal materials for photocatalysis and electrochemical energy storage and conversion

This perspective reviews recent advances in inverse opal structures, how they have been developed, studied and applied as catalysts, catalyst support materials, as electrode materials for batteries, water splitting applications, solar-to-fuel conversion and electrochromics, and finally as photonic photocatalysts and photoelectrocatalysts. Throughout, we detail some of the salient optical characteristics that underpin recent results and form the basis for light-matter interactions that span electrochemical energy conversion systems as well as photocatalytic systems. Strategies for using 2D as well as 3D structures, ordered macroporous materials such as inverse opals are summarized and recent work on plasmonic–photonic coupling in metal nanoparticle-infiltrated wide band gap inverse opals for enhanced photoelectrochemistry are provided

Effects of Food Bar Chewing Duration on the Physiologic, Metabolic, and Perceptual Responses to Moderate-Intensity Running

Purpose Chewing duration can affect food particle size, gastric processing, and postprandial glycemia, but these effects have not been investigated with exercise. This study examined how the chewing duration of a food bar impacts glycemic and metabolic responses, gastrointestinal (GI) symptoms, psychological affect, and performance during endurance running. Methods This randomized, unblinded, crossover study had 15 males (35.2 ± 7.4 years, VO2peak: 56.1 ± 5.2 ml/kg/min) attend three laboratory visits. Visit 1 required a VO2peak test, 10 min familiarization run at 60% VO2peak, and familiarization time-to-exhaustion (TTE) test (10 min at 90% VO2peak, followed by TTE at 100% VO2peak). Visits 2 and 3 consisted of a 60 min run at 60% VO2peak, followed by TTE testing. Participants were fed 45 g of a bar (180 kcal, 4 g fat, 33 g carbohydrate, 3 g protein, 1 g fiber) in 9 g servings 30 min before running, and 27 g of bar in 9 g servings at three timepoints during the 60 min run. Participants consumed the servings in 20 (20CHEW) or 40 (40CHEW) masticatory cycles, at 1 chew/second. Outcomes included blood glucose, substrate use, GI symptoms, perceived exertion (RPE), overall feeling, and TTE. Results Post-prandial blood glucose, GI symptoms, and RPE increased over time, but there were no significant between-condition or condition-by-time effects. TTE showed no significant between-condition effect (20CHEW: 288 ± 133 s; 40CHEW: 335 ± 299 s; p = 0.240). Overall feeling demonstrated a time-by-condition effect (p = 0.006), suggesting possible better maintenance over time with 40CHEW. Conclusion Cumulatively, the results suggest that extended chewing minimally impacts physiology, perceptions, and performance during 60 min moderate-intensity running

Patterning optically clear films: co-planar transparent and color-contrasted thin films from interdiffused electrodeposited and solution-processed metal oxides

Transparent thin films can now be site-selectively patterned and positioned on surface using mask-defined electrodeposition of one oxide and overcoating with a different solution-processed oxide, followed by thermal annealing. Annealing allows an interdiffusion process to create a new oxide that is entirely transparent. A primary electrodeposited oxide can be patterned and the secondary oxide coated over the entire substrate to form high color contrast coplanar thin film tertiary oxide. The authors also detail the phase formation and chemical state of the oxide and how the nature of the electrodeposited layer and the overlayer influence the optical clearing of the patterned oxide film

High performance inverse opal Li-ion battery with paired intercalation and conversion mode electrodes

Structured porous materials have provided several breakthroughs that have facilitated high rate capability, better capacity retention and material stability in Li-ion batteries. However, most advances have been limited to half cells or lithium batteries, and with a single mode of charge storage (intercalation, conversion, or alloying etc.). The use of dual-mode charge storage with non-traditional material pairings, while maintaining the numerous benefits of nanoscale materials, could significantly improve the capacity, energy density, stability and overall battery safety considerably. Here, we demonstrate an efficient, high capacity full inverse opal Li-ion battery with excellent cycle life, where both the cathode and anode binder-free electrodes are composed of 3D nanocrystal assemblies as inverse opal (IO) structures of intercalation-mode V2O5 IO cathodes and conversion-mode Co3O4 IO anodes. Electrochemically charged Co3O4 IOs function as Li-ion anodes and the full V2O5/Co3O4 cell exhibits superior performance compared to lithium batteries or half cells of either IO material, with voltage window compatibility for high capacity and energy density. Through asymmetric charge-discharge tests, the V2O5 IO/Co3O4 IO full Li-ion cell can be quickly charged, and discharged both quickly and slowly without any capacity decay. We demonstrate that issues due to the decomposition of the electrolyte with increased cycling can be overcome by complete electrolyte infiltration to remove capacity fading from long term cycling at high capacity and rate. Lastly, we show that the V2O5 IO/Co3O4 IO full Li-ion cells cycled in 2 and 3-electrode flooded cells maintain 150 mA h g-1 and remarkably, show no capacity fade at any stage during cycling for at least 175 cycles. The realization of an all-3D structured anode and cathode geometry with new mutually co-operative dual-mode charge storage mechanisms and efficient electrolyte penetration to the nanocrystalline network of material provides a testbed for advancing high rate, high capacity, stable Li-ion batteries using a wide range of materials pairings

Growing oxide nanowires and nanowire networks by solid state contact diffusion into solution‐processed thin films

New techniques to directly grow metal oxide nanowire networks without the need for initial nanoparticle seed deposition or postsynthesis nanowire casting will bridge the gap between bottom‐up formation and top‐down processing for many electronic, photonic, energy storage, and conversion technologies. Whether etched top‐down, or grown from catalyst nanoparticles bottom‐up, nanowire growth relies on heterogeneous material seeds. Converting surface oxide films, ubiquitous in the microelectronics industry, to nanowires and nanowire networks by the incorporation of extra species through interdiffusion can provide an alternative deposition method. It is shown that solution‐processed thin films of oxides can be converted and recrystallized into nanowires and networks of nanowires by solid‐state interdiffusion of ionic species from a mechanically contacted donor substrate. NaVO3 nanowire networks on smooth Si/SiO2 and granular fluorine‐doped tin oxide surfaces can be formed by low‐temperature annealing of a Na diffusion species‐containing donor glass to a solution‐processed V2O5 thin film, where recrystallization drives nanowire growth according to the crystal habit of the new oxide phase. This technique illustrates a new method for the direct formation of complex metal oxide nanowires on technologically relevant substrates, from smooth semiconductors, to transparent conducting materials and interdigitated device structures

High capacity binder-free nanocrystalline GeO2 inverse opal anodes for Li-ion batteries with long cycle life and stable cell voltage

We demonstrate that crystalline macroporous GeO2 inverse opals exhibit state-of-the-art capacity retention, voltage stability and a very long cycle life when tested as anode materials for Li-ion batteries. The specific capacities and capacity retention obtained from GeO2 IOs are greater than values reported for other GeO2 nanostructures and comparable to pure Ge nanostructures. Unlike pure Ge nanostructures, GeO2 IOs can be prepared in air without complex processing procedures, potentially making them far more attractive from an industrial point of view, in terms of cost and ease of production. Inverse opals are structurally and electrically interconnected, and remove the need for additives and binders. GeO2 IOs show gradual capacity fading over 250 and 1000 cycles, when cycled at specific currents of 150 and 300 mA/g, respectively, while maintaining high capacities and a stable overall cell voltage. The specific capacities after the 500th and 1000th cycles at a specific current of 300 mA/g were ~ 632 and 521 mA h/g respectively, corresponding to a capacity retention in each case of ~ 76% and 63% from the 2nd cycle. Systematic analysis of differential capacity plots obtained from galvanostatic voltage profiles over 1000 cycles offers a detailed insight into the mechanism of charge storage in GeO2 anodes over their long cycle life. Rate capability testing and asymmetric galvanostatic testing demonstrate the ability of GeO2 IO samples to deliver significantly high capacities even at high specific currents (1 A/g)

Electrodeposited structurally stable V2O5 inverse opal networks as high performance thin film lithium batteries

High performance thin film lithium batteries using structurally stable electrodeposited V2O5 inverse opal (IO) networks as cathodes provide high capacity and outstanding cycling capability and also were demonstrated on transparent conducting oxide current collectors. The superior electrochemical performance of the inverse opal structures was evaluated through galvanostatic and potentiodynamic cycling, and the IO thin film battery offers increased capacity retention compared to micron-scale bulk particles from improved mechanical stability and electrical contact to stainless steel or transparent conducting current collectors from bottom-up electrodeposition growth. Li+ is inserted into planar and IO structures at different potentials, and correlated to a preferential exposure of insertion sites of the IO network to the electrolyte. Additionally, potentiodynamic testing quantified the portion of the capacity stored as surface bound capacitive charge. Raman scattering and XRD characterization showed how the IO allows swelling into the pore volume rather than away from the current collector. V2O5 IO coin cells offer high initial capacities, but capacity fading can occur with limited electrolyte. Finally, we demonstrate that a V2O5 IO thin film battery prepared on a transparent conducting current collector with excess electrolyte exhibits high capacities (∼200 mAh g–1) and outstanding capacity retention and rate capability

Pseudocapacitive charge storage at nanoscale silicon electrodes

Pseudocapacitive behaviour can be accessed when Si nanowire (NW) electrodes are scanned at relatively fast potential scan rates in Li-ion battery electrolytes. Measurements using cyclic voltammetry supported by electron microscopy confirm that Si NWs formed on silicon substrates, as opposed to metallic current collectors, do not solely undergo alloying reactions. The influence of doping type, carrier concentration and bias condition during voltammetric polarization significantly alters the mechanism of electrochemical energy storage. The formation of a carrier depleted (electrically dead) layer of n-type NWs on silicon current collector electrodes limits insertion or alloying processes and rates that ordinarily form Li-Si phases, and charge is also stored within the electric double layer via pseudocapacitive processes. P-type NWs with solid crystalline cores also exhibit pseudocapacitive charge storage without structural modification of the NWs

Inverse relation between clinical distractibility and Stroop interference in functional psychoses

INTRODUCTION: Many patients with psychotic disorders appear distractible. Some theories propose that distractibility causes psychotic symptoms, others propose the reverse. We tested these theories by assessing relations between psychotic symptoms, Stroop interference, and clinical distractibility in patients with schizophrenia or affective psychoses. METHODS: We rated clinical distractibility in patients with acute schizophrenia or affective psychoses and measured their Stroop interference in a single trial colour-naming task. RESULTS:  Clinical distractibility related inversely to Stroop interference. Stroop interference was small in drug-naive patients with schizophrenia, but normal in those receiving treatment. Patients with affective psychoses showed the opposite pattern. CONCLUSIONS: The abnormality of attention that clinicians rate as “distractibility” is probably the opposite—attentional capture. Abnormal attention neither results from nor causes psychotic symptoms. Rather, it is an independent correlate of pathophysiology in functional psychoses that merits assessment and treatment in its own right