Thermodynamic and Physical Properties of Molten Sodium Polysulfides from Open-Circuit Voltage Measurements

1972 ◽  
Vol 119 (8) ◽  
pp. 1033 ◽  
Author(s):  
Nirmal K. Gupta ◽  
Ragnar P. Tischer
Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1976
Author(s):  
Junyoung Choi ◽  
Kwansoo Yang ◽  
Hyeon-Su Bae ◽  
Isheunesu Phiri ◽  
Hyun Jeong Ahn ◽  
...  

To inhibit Li-dendrite growth on lithium (Li)-metal electrodes, which causes capacity deterioration and safety issues in Li-ion batteries, we prepared a porous polyimide (PI) sponge using a solution-processable high internal-phase emulsion technique with a water-soluble PI precursor solution; the process is not only simple but also environmentally friendly. The prepared PI sponge was processed into porous PI separators and used for Li-metal electrodes. The physical properties (e.g., thermal stability, liquid electrolyte uptake, and ionic conductivity) of the porous PI separators and their effect on the Li-metal anodes (e.g., self-discharge and open-circuit voltage properties after storage, cycle performance, rate capability, and morphological changes) were investigated. Owing to the thermally stable properties of the PI polymer, the porous PI separators demonstrated no dimensional changes up to 180 °C. In comparison with commercialized polyethylene (PE) separators, the porous PI separators exhibited improved wetting ability for liquid electrolytes; thus, the latter improved not only the physical properties (e.g., improved the electrolyte uptake and ionic conductivity) but also the electrochemical properties of Li-metal electrodes (e.g., maintained stable self-discharge capacity and open-circuit voltage features after storage and improved the cycle performance and rate capability) in comparison with PE separators.


2003 ◽  
Vol 762 ◽  
Author(s):  
Jianhua Zhu ◽  
Vikram L. Dalal

AbstractWe report on the growth and properties of microcrystalline Si:H and (Si,Ge):H solar cells on stainless steel substrates. The solar cells were grown using a remote, low pressure ECR plasma system. In order to crystallize (Si,Ge), much higher hydrogen dilution (∼40:1) had to be used compared to the case for mc-Si:H, where a dilution of 10:1 was adequate for crystallization. The solar cell structure was of the p+nn+ type, with light entering the p+ layer. It was found that it was advantageous to use a thin a-Si:H buffer layer at the back of the cells in order to reduce shunt density and improve the performance of the cells. A graded gap buffer layer was used at the p+n interface so as to improve the open-circuit voltage and fill factor. The open circuit voltage and fill factor decreased as the Ge content increased. Quantum efficiency measurements indicated that the device was indeed microcrystalline and followed the absorption characteristics of crystalline ( Si,Ge). As the Ge content increased, quantum efficiency in the infrared increased. X-ray measurements of films indicated grain sizes of ∼ 10nm. EDAX measurements were used to measure the Ge content in the films and devices. Capacitance measurements at low frequencies ( ~100 Hz and 1 kHz) indicated that the base layer was indeed behaving as a crystalline material, with classical C(V) curves. The defect density varied between 1x1016 to 2x1017/cm3, with higher defects indicated as the Ge concentration increased.


Author(s):  
Pietro Caprioglio ◽  
Fengshuo Zu ◽  
Christian M. Wolff ◽  
Martin Stolterfhot ◽  
Norbert Koch ◽  
...  

2019 ◽  
Author(s):  
Ulrich W. Paetzold ◽  
Saba Gharibzadeh ◽  
Marius Jackoby ◽  
Tobias Abzieher ◽  
Somayeh Moghadamzadeh ◽  
...  

2019 ◽  
Author(s):  
Kristina M. Winkler ◽  
Ines Ketterer ◽  
Alexander J. Bett ◽  
Özde Kabakli ◽  
Martin Bivour ◽  
...  

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