FABRICATION OF THIN-FILM LIMN2O4 CATHODES FOR RECHARGEABLE MICROBATTERIES

We have fabricated thin-film cathodes of lithiated manganese oxide (Li(x)Mn2O4, where x less-than-or-equal-to 1), which can reversibly intercalate nearly one Li atom per unit formula, at a steady potential of 4.1 V. This results in a theoretical energy density of about 600 Wh/kg. The polycrystalline films (thickness of 0.5-2-mu-m) show electrochemical performance exceeding that of bulk materials. This is attributed to the small grain size and the porosity within these Li(x)Mn2O4 three-dimensional spinel films, reducing the diffusion path length for Li+ ions. The films are tested as the cathodes in about 70 charging/discharging cycles, in a secondary lithium cell, at current rates of 10-100-mu-A cm-2. No measurable self-discharge over 12 h periods is observed. These thin-film cathodes with above electrochemical properties are very promising for a new generation thin-film secondary batteries

THE SPINEL PHASE OF LIMN2O4 AS A CATHODE IN SECONDARY LITHIUM CELLS

The electrochemical properties of LiMn2O4 and LiMyMn2-yO4 (M = Ti, Ge, Fe, Zn, or Ni) were studied for different conditions of sample preparation and different degrees of cation substitution (y). In the voltage range 3.5-4.5 V, cells of either spinel LiMn2O4 or lambda-MnO2 (made by leaching the Li from LiMn2O4) reversibly insert 0.4 Li per Mn at an average voltage of 4.1 V, leading to an energy density of 480 Wh/kg of cathode. Cells cycled 50 times lost less than 10% of their initial capacity, suggesting that this material could be used instead of LiCoO2 or LiNiO2 as the cathode in the new generation of "rocking chair batteries." Replacing Mn with cations of valence 2 (Ni, Zn) or 3 (Fe) reduces the amount of Mn+3 and correspondingly reduces the capacity of the cells at 4.1 V, but does not affect their cycling performance

LOW-TEMPERATURE LIMN2O4 SPINEL FILMS FOR SECONDARY LITHIUM BATTERIES

Low temperature thin film LixMn2O4 spinel, with x congruent-to 1, are fabricated for use in secondary batteries. The spinel crystal structure is obtained by in situ postdeposition annealing of the films at temperatures as low as 400-degrees-C. Such temperatures are compatible with semiconductor processing, permitting future integration of the batteries with electronics. 1-3-mu-m thin LiMn2O4 films are tested in LiMn2O4/EC + DEE + LiClO4/Li arrangements. They intercalate nearly one Li+ ion at an average potential of 4.1 V and show very good intercalation kinetics, so that a 10 C discharge rate produces an energy density of 500 W-h per kilogram of active cathode material. These LiMn2O4 filMS show very promising cycle life, even at 55-degrees-C. Films cycled more than 220 times maintain more than 70% of their original capacity

Li-rich thin film cathode prepared by pulsed laser deposition

10.1038/srep03332Scientific Reports3

HIV Knowledge, Attitudes, and Practices of Young People in Iran: Findings of a National Population-Based Survey in 2013

INTRODUCTION:The evidence is mixed on the HIV knowledge, attitude, and practices of youth in Iran. The aim of the current study was to assess knowledge, attitudes, and practices of Iranian youth towards HIV through a national survey. MATERIALS AND METHODS:Through a cross-sectional study with multistage cluster sampling, we administered a pilot-tested standard questionnaire to assess the levels of HIV knowledge, attitudes and practices of individuals aged 15-29 years old. Participants were recruited from 13 provinces in Iran and consisted of 2456 men and 2412 women. RESULTS:Only 37.3% of the participants had a high knowledge score. Most participants knew the main routes of HIV transmission; however, misconceptions existed about the transmission of HIV through mosquito bites across all age groups (31.7% correct response). Positive levels of attitude wereobserved among 20.7% of the participants. Most participants believed that people living with HIV (PLHIV) should be supported (88.3%) while only 46.3% were ready to share a table with them. Among those aged 19-29 years old, the main source of HIV information was mass media (69.1%), only 13.1% had ever tested for HIV, around 20.8% had ever had extramarital sex (31.7% male vs. 9.6% female),1.8% ever injected drugs (2.9% male vs. and 0.7% female). Among sexually active subjects in this age group, only 21.8% (26.1% male vs. 7.1% female) were consistent condom users. CONCLUSIONS:The findings showed that Iranian youth and young adults have relatively insufficient overall knowledge and negative attitudes about HIV and PLHIV. Novel strategies involving schools and youth's networks could be employed to deliver a culturally sensitive sexual health program