Nanosized nickel hexacyanoferrate modified screen-printed electrodes as flexible supercabattery platforms: Influence of annealing temperatures and supporting electrolytes

Water-insoluble nickel hexacyanoferrate Ni3[Fe(CN)6]2.nH2O (NiHCF) nanoparticles were synthesized via a facile precipitation method in the presence of polyvinylpyrrolidone (PVP) and sodium citrate (SC). Large-scale production of cubic NiHCF crystals with an average diameter of 35 nm and a specific surface area (SBET) of 452.9 m2/g was shown to be possible. The NiHCF nanoparticles were drop-cast upon screen-printed graphite macroelectrode surfaces (SPEs) allowing a flexible energy storage device to be realised. The tunable pore size and dual functional reactive sites offered superior specific capacitances of 197.5, 139.35, 356.25, and 406.25 F/g in 0.1 M KCl, 0.1 M NaCl, 0.1 M NaOH and 0.1 M KOH, respectively at a current density of 5 A/g. The highest capacitance was found using 0.1 M KOH supporting electrolyte due to the combination of surface (intercalation/de-intercalation of A+) and faradaic processes (M2+/M3+) as supercabattery platforms. The thermal treatment of the NiHCF samples at 100, 200, 300 °C were performed within oxygen and nitrogen atmospheres and the specific capacitances were measured in 0.1 M KOH. Interestingly, the specific capacitance increases up to 546 F/g for NiHCF annealed at 100 °C in oxygen and reduces to 342 F/g if NiHCF when annealed at 200 °C in nitrogen atmospheres due to the likely introduction of diverse vacancies. Furthermore, the NiHCF/SPEs were investigated in an as-symmetric two-electrode system, which revealed a specific capacitance of 570 F/g at 5 A/g. The NiHCF/SPE exhibited high capability rate, capacitive retention and excellent cycling stabilities particularly if NiHCF was annealed within a nitrogen atmosphere. Thus, the NiHCF supercabattery platforms can be used for developing new flexible energy storage devices

Photoperiod Regulates Lean Mass Accretion, but Not Adiposity, in Growing F344 Rats Fed a High Fat Diet

yesIn this study the effects of photoperiod and diet, and their interaction, were examined for their effects on growth and body composition in juvenile F344 rats over a 4-week period. On long (16L:8D), relative to short (8L:16D), photoperiod food intake and growth rate were increased, but percentage adiposity remained constant (ca 3-4%). On a high fat diet (HFD), containing 22.8% fat (45% energy as fat), food intake was reduced, but energy intake increased on both photoperiods. This led to a small increase in adiposity (up to 10%) without overt change in body weight. These changes were also reflected in plasma leptin and lipid levels. Importantly while both lean and adipose tissue were strongly regulated by photoperiod on a chow diet, this regulation was lost for adipose, but not lean tissue, on HFD. This implies that a primary effect of photoperiod is the regulation of growth and lean mass accretion. Consistent with this both hypothalamic GHRH gene expression and serum IGF-1 levels were photoperiod dependent. As for other animals and humans, there was evidence of central hyposomatotropism in response to obesity, as GHRH gene expression was suppressed by the HFD. Gene expression of hypothalamic AgRP and CRH, but not NPY nor POMC, accorded with the energy balance status on long and short photoperiod. However, there was a general dissociation between plasma leptin levels and expression of these hypothalamic energy balance genes. Similarly there was no interaction between the HFD and photoperiod at the level of the genes involved in thyroid hormone metabolism (Dio2, Dio3, TSHβ or NMU), which are important mediators of the photoperiodic response. These data suggest that photoperiod and HFD influence body weight and body composition through independent mechanisms but in each case the role of the hypothalamic energy balance genes is not predictable based on their known function.Scottish Government (Rural and Environment Science and Analytical Services Division, http://www.scotland.gov.uk/), AWR LR LMT PJM and the BBSRC, (http://www.bbsrc.ac.uk/home/home.aspx, grant BB/K001043/1), AWR GH PJ