Basis Of Energy Density Research Articles

A comparative study on emulsification in the presence of a nanoclay (Pickering emulsion) or a surfactant using high intensity mixing

The study explored the potential of using a nanoclay, Laponite RD, as a stabilizing agent in comparison to a surfactant, Tergitol TMN6, at dispersed phase volume fractions of 10–50% vol. An ultrasonicator was employed as an energy intensive device; covering a specific power input range of ∼ 36–52 W kg− 1. In both cases, final dispersions obtained could be considered stable over the period of ageing tests for 3 months as comparable drop size distributions were obtained although there were some differences in the rheology at the highest dispersed phase concentration. Whilst surfactant stabilized emulsions were of Newtonian behavior, Pickering emulsions stabilized with the nanoclay exhibited non-Newtonian behavior, which may be a desirable feature of the final product- certainly one that requires attention in design and scale up. Kinetics of breakup studied through the evolution of the Sauter mean diameter prior to reaching an equilibrium value on the basis of energy density have shown the breakup process being faster with the Pickering emulsions although the equilibrium drop diameters were larger. Overall, with emulsions stabilized using a surfactant, Sauter mean drop diameters could be as low as 240 nm, regardless of the dispersed phase volume fraction, drop sizes were larger with Pickering emulsions which depended on the dispersed phase concentration.

Efficient Stabilization of Na Storage Reversibility by Ti Integration into O′3-Type NaMnO 2

The development of an energy storage system with abundant elements is a key challenge for a sustainable society, and the interest of Na intercalation chemistry is extending throughout the research community. Herein, the impact of Ti integration into NaMnO 2 in a binary system of x NaMnO 2 –( 1 – x ) TiO 2 ( 0.5 ≤ x ≤ 1 ) is systematically examined for rechargeable Na battery applications. Stoichiometric NaMnO 2 , which is classified as an in-plane distorted O ′ 3-type layered structure, delivers a large initial discharge capacity of approximately 200 mAh g -1 , but insufficient capacity retention is observed, most probably associated with dissolution of Mn ions on electrochemical cycles. Ti-substituted samples show highly improved electrode performance as electrode materials. However, the appearance of a sodium-deficient phase, Na 4 Mn 4 Ti 5 O 18 with a tunnel-type structure, is observed for Ti-rich phases. Among the samples in this binary system, Na 0.8 Mn 0.8 Ti 0.2 O 2 ( x = 0.8 ), which is a mixture of a partially Ti-substituted O ′ 3-type layered oxide (Na 0.88 Mn 0.88 Ti 0.12 O 2 ) and tunnel-type Na 4 Mn 4 Ti 5 O 18 as a minor phase elucidated by Rietveld analysis on both neutron and X-ray diffraction patterns, shows good electrode performance on the basis of energy density and cyclability. Both phases are electrochemically active as evidenced by in situ X-ray diffraction study, and the improvement of reversibility originates from the suppression of Mn dissolution on electrochemical cycles. From these results, the feasibility of Mn-based electrode materials for high-energy rechargeable Na batteries made from only abundant elements is discussed in detail.

Practical energy densities, cost, and technical challenges for magnesium‐sulfur batteries

AbstractAmid burgeoning environmental concerns, electrochemical energy storage has rapidly gained momentum. Among the contenders in the “beyond lithium” energy storage arena, the magnesium‐sulfur (Mg/S) battery has emerged as particularly promising, owing to its high theoretical energy density. However, the gap between fundamental research and practical application is still hindering the commercialization of Mg/S batteries. Here, through reviewing the recent developments of Mg/S batteries technologies, especially with respect to energy density and cost, we present the primary technical challenges on both materials and device level to surpass the energy density and cost‐effectiveness of lithium‐ion battery. While the high electrolyte‐sulfur ratio and the expensive liquid electrolyte are significantly limiting the practical application of Mg/S batteries, we found that solid‐state Mg electrolyte appears to be a feasible solution on the basis of energy density and cost evaluation.image

A New “Solution” Towards Wet Chemical Processing of Lithium Garnet Films

Lithium solid electrolytes are expected to improve next-generation energy storage technology on the basis of energy density, safety, and cost. However, there has been limited success in mass producing a solid separator with transport properties and comparable thickness to a traditional polypropylene separator used in lithium-ion batteries. This problem is especially difficult with oxide-based solid electrolytes, such as Li7-3xAlxLa3Zr2O12 (LLZO), where thin films between 200 nm and 5 µm in thickness using scalable solution-based techniques have heretofore not been realized. Several vacuum-based1,2 and sol-gel-derived3,4 methods have shown promise in making thin garnet-based solid electrolyte films with relatively high ionic conductivity (~10-6 - 10-5 S/cm at room temperature), yet lithium loss during post annealing can alter the phase as well as significantly affect the lithium ion conductivity. Only a recent report5 has overcome this issue by using an alternative ceramic processing strategy establishing lithium reservoirs directly in lithium garnet-based films (through Li3N multilayers) that allow for lithiated and fast-conducting cubic LLZO electrolytes at unusually low processing temperatures using pulsed laser deposition. Still, the exploration of scalable fabrication techniques is of special importance to develop thin films of garnet-based solid electrolytes with high ionic conductivity. Here, we present a new technique based on spray pyrolysis for growing LLZO thin films. We show that the crystallization and the phase transformation can be modulated to lower temperatures (<750 °C) by tuning the concentration of cations and the boiling point of the solvents used in the spray solution. Also, by altering the chemistry of the spray solution and the post-annealing conditions, we show that the surface roughness can be modulated while still maintaining dense and continuous membranes of LLZO. Our results highlight a new opportunity for manufacturing garnet-based solid electrolytes with tunable electrochemical surface areas. The insights from this work are expected to serve as fundamental guidelines for future optimization toward solution-based processing of thin film superionic garnet-based materials for next-generation lithium metal batteries. Acknowledgements This research was supported by Samsung Electronics and a portion of this research was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.

Breakup of nanoparticle clusters using Microfluidizer M110-P

A commercial design, bench scale microfluidic processor, Microfluidics M110-P, was used to study the deagglomeration of clusters of nanosized silica particles. Breakup kinetics, mechanisms and the smallest attainable size were determined over a range of particle concentrations of up to 17% wt. in water and liquid viscosities of up to 0.09Pas at 1% wt. particle concentration. The device was found to be effective in achieving complete breakup of agglomerates into submicron size aggregates of around 150nm over the range covered. A single pass was sufficient to achieve this at a low particle concentration and liquid viscosity. As the particle concentration or continuous phase viscosity was increased, either a higher number of passes or a higher power input (for the same number of passes) was required to obtain a dispersion with a size distribution in the submicron range.Breakup took place through erosion resulting in a dispersion of a given mean diameter range regardless of the operating condition. This is in line with results obtained using rotor-stators. Breakup kinetics compared on the basis of energy density indicated that whilst Microfluidizer M110-P and an in-line rotor-stator equipped with the emulsor screen are of similar performance at a viscosity of 0.01Pas, fines volume fraction achieved with the Microfluidizer was much higher at a viscosity of 0.09Pas.

Dietary complementation by wild birds: Considerations for field studies

Free-living birds must satisfy fluctuating nutrient requirements in diverse and varying environments. Ingesting nutritionally complementary foods may be the most effective means by which wild birds match nutrient ingestion and nutrient needs. Dietary complementation may occur fortuitously when foods chosen in response to non-nutritive factors (e.g. competition, predation risk, food colour), or on the basis of energy density, also fulfill specific nutrient needs (passive dietary complementation). In some environments, especially during productive phases (e.g. reproduction), free-living birds may rely on nutrient appetites to ensure their choice of foods satisfies their nutrient needs (active dietary complementation). Meeting nutrient needs through dietary complementation can be facilitated, complicated, or impeded by any of several environmental or organism determinants of food choice. Nutrient appetites, exogenous food stores, and endogenous nutrient stores are three organismal determinants that are probably the most important in facilitating dietary complementation.

Diurnal feeding and drinking patterns of adult cats as affected by changes in the level of fat in the diet

A continuous on-line computerized monitoring system was used to measure food and water intake patterns of mature cats during consecutive low-fat (3 week) or high-fat (3 week) feeding. Cats consumed less of the high-fat than the low-fat diet such that their mean daily gross energy intake was the same for both diets. It was concluded that cats regulate their daily food intake on the basis of energy density. High-fat substitution caused a reduction in the quantity of food consumed in the dark cycle. There was no apparent change in either the light- or dark-cycle meal frequency, both the light- and dark-cycle average meal size were curtailed. Water intake did not vary significantly between low- and high-fat diets. There was no significant difference in number of drinking bouts or average bout volume for the low- and high-fat diets in both the light and dark cycles. Two diet-choice trials produced no clear preference for the low- or high-fat diet. It appears that the fat content, independent of flavor components or physical consistency, has little effect on dietary preference of the cat.