scholarly journals Highly Stable Porous Polyimide Sponge as a Separator for Lithium-Metal Secondary Batteries

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1976
Author(s):  
Junyoung Choi ◽  
Kwansoo Yang ◽  
Hyeon-Su Bae ◽  
Isheunesu Phiri ◽  
Hyun Jeong Ahn ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Physical Properties ◽  
Open Circuit Voltage ◽  
Morphological Changes ◽  
Rate Capability ◽  
Open Circuit ◽  
Water Soluble ◽  
Cycle Performance ◽  
Metal Electrodes ◽  
Electrolyte Uptake

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.

scholarly journals Wearable Device Oriented Flexible and Stretchable Energy Harvester Based on Embedded Liquid-Metal Electrodes and FEP Electret Film

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 458
Author(s):  
Jianbing Xie ◽  
Yiwei Wang ◽  
Rong Dong ◽  
Kai Tao
Keyword(s):  
Liquid Metal ◽  
Energy Harvester ◽  
Open Circuit Voltage ◽  
Electric Energy ◽  
Open Circuit ◽  
Metal Electrodes ◽  
Conductive Film ◽  
Stretchable Electrode ◽  
Liquid Metal Alloy ◽  
Elbow Motion

In this paper, a flexible and stretchable energy harvester based on liquid-metal and fluorinated ethylene propylene (FEP) electret films is proposed and implemented for the application of wearable devices. A gallium liquid-metal alloy with a melting point of 25.0 °C is used to form the stretchable electrode; therefore, the inducted energy harvester will have excellent flexibility and stretchability. The solid-state electrode is wrapped in a dragon-skin silicone rubber shell and then bonded with FEP electret film and conductive film to form a flexible and stretchable energy harvester. Then, the open-circuit voltage of the designed energy harvester is tested and analyzed. Finally, the fabricated energy harvester is mounted on the elbow of a human body to harvest the energy produced by the bending of the elbow. The experimental results show that the flexible and stretchable energy harvester can adapt well to elbow bending and convert elbow motion into electric energy to light the LED in a wearable watch.

Morphological changes in the electrodes of phosphoric acid fuel cells operating under open circuit voltage conditions

1990 ◽  
Vol 20 (2) ◽  
pp. 235-239 ◽  
Author(s):  
V. Alderucci ◽  
E. Passalacqua ◽  
N. Giordano ◽  
P. L. Antonucci ◽  
F. Parmigiani ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Phosphoric Acid ◽  
Open Circuit Voltage ◽  
Morphological Changes ◽  
Open Circuit ◽  
Phosphoric Acid Fuel Cells

An approach to high open-circuit voltage polymer solar cells via alcohol/water-soluble cathode interlayers based on anthrathiadiazole derivatives

2017 ◽  
Vol 41 (21) ◽  
pp. 13166-13174 ◽  
Author(s):  
Yang Miao ◽  
Tong Yang ◽  
Zong Cheng ◽  
Yuewei Zhang ◽  
Jingying Zhang ◽  
...  
Keyword(s):  
Solar Cells ◽  
High Performance ◽  
Open Circuit Voltage ◽  
Polymer Solar Cells ◽  
Open Circuit ◽  
Water Soluble ◽  
High Performance Polymer ◽  
Alcohol Water ◽  
Water Alcohol

Two water/alcohol-soluble small molecular cathode interlayers (CILs) were synthesized and employed to fabricate high performance polymer solar cells (PSCs) with a large open-circuit voltage (Voc) of 0.93 V.

scholarly journals Design of A High Performance Zeolite/Polyimide Composite Separator for Lithium-Ion Batteries

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 764 ◽  
Author(s):  
Yanling Li ◽  
Xiang Wang ◽  
Jianyu Liang ◽  
Kuan Wu ◽  
Long Xu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Lithium Ion Batteries ◽  
Phase Inversion ◽  
High Performance ◽  
Rate Capability ◽  
Lithium Ion ◽  
Cycle Performance ◽  
Electrolyte Uptake ◽  
Composite Separator ◽  
Free Transport

A zeolite/polyimide composite separator with a spongy-like structure was prepared by phase inversion methods based on heat-resistant polyimide (PI) polymer matrix and ZSM-5 zeolite filler, with the aim to improve the thermal stability and electrochemical properties of corresponding batteries. The separator exhibits enhanced thermal stability and no shrinkage up to 180 °C. The introduction of a certain number of ZSM-5 zeolites endows the composite separator with enhanced wettability and electrolyte uptake, better facilitating the free transport of lithium-ion. Furthermore, the composite separator shows a high ionic conductivity of 1.04 mS cm−1 at 25 °C, and a high decomposition potential of 4.7 V. Compared with the PP separator and pristine PI separator, the ZSM-5/PI composite separator based LiFePO4/Li cells have better rate capability (133 mAh g−1 at 2 C) and cycle performance (145 mAh g-1 at 0.5 C after 50 cycles). These results demonstrate that the ZSM-5/PI composite separator is promising for high-performance and high-safety lithium-ion batteries.

Fabrication of hybrid gel nanofibrous polymer electrolyte for lithium ion battery

2018 ◽  
Vol 32 (19) ◽  
pp. 1840066 ◽  
Author(s):  
Monali V. Bhute ◽  
Subhash B. Kondawar ◽  
Pankaj Koinkar
Keyword(s):  
Lithium Ion Battery ◽  
Polymer Electrolyte ◽  
Ethylene Carbonate ◽  
Gel Polymer Electrolyte ◽  
Rate Capability ◽  
Lithium Ion ◽  
Cycle Performance ◽  
High Porosity ◽  
Hybrid Gel ◽  
Electrolyte Uptake

Fibrous membranes are promising separators for high-performance lithium ion battery because of their high porosity and superior electrolyte uptake. In this paper, the fabrication of hybrid gel polymer electrolyte (HGPE) by introducing SnO2 nanoparticles in poly(vinylidine fluoride) by electrospinning technique and soaking the electrospun nanofibrous membranes in 1 M LiPF6 in ethylene carbonate (EC)/diethyl carbonate (DEC) (1:1, v/v). The as-prepared electrospun HGPE with SnO2 nanofiller was characterized by scanning electron microscopy. The influence of SnO2 on the structure of polymer membrane, physical, and electrochemical properties is systematically investigated. HGPE shows significant high ionic conductivity 4.6 × 10[Formula: see text] S/cm at room-temperature and better cell performance such as discharge C-rate capability and cycle performance. The hybrid gel polymer nanofibrous membrane favors high uptake of lithium electrolyte so that electrolyte leakage is reduced. The gel polymer electrolyte with SnO2 filler was used for the fabrication of Li/PVdF-SnO2/LiFePO4 coin cell. The fabricated cell was evaluated at a current density of 0.2 C-rate and delivered stable and excellent cycle performance. This study revealed that the prepared HGPE can be employed as potential electrolyte for lithium ion batteries.

Microcrystalline (Si,Ge):H Solar Cells

2003 ◽  
Vol 762 ◽  
Author(s):  
Jianhua Zhu ◽  
Vikram L. Dalal
Keyword(s):  
Solar Cells ◽  
Buffer Layer ◽  
Quantum Efficiency ◽  
Fill Factor ◽  
Open Circuit Voltage ◽  
Defect Density ◽  
Cell Structure ◽  
Open Circuit ◽  
Base Layer ◽  
Ecr Plasma

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.

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