scholarly journals Self-Polymerized Dopamine Nanoparticles Modified Separators for Improving Electrochemical Performance and Enhancing Mechanical Strength of Lithium-Ion Batteries

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 648 ◽  
Author(s):  
Wenqian Hao ◽  
Dechong Kong ◽  
Jiamiao Xie ◽  
Yaping Chen ◽  
Jian Ding ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Mechanical Strength ◽  
Lithium Ion Batteries ◽  
Ionic Conductivities ◽  
Lithium Ion ◽  
Thermal Shrinkage ◽  
Thermal Stabilities ◽  
Electrochemical Testing ◽  
Adhesion Ability ◽  
Electrolyte Uptake

Separators in lithium-ion batteries (LIBs) play an important role for battery safety, so stable electrochemical performance and high mechanical strength of separators will always be of interest. On the basis of the fact that polydopamine (PDA) nanoparticles found in mussel have a strong adhesion ability, biomaterial surface nanoparticles modification methods are developed to increase electrochemical performance and enhance mechanical strength of polypropylene (PP) and polypropylene/polyethylene/polypropylene (PP/PE/PP) separators. The electrolyte uptake performance, ionic conductivities, discharging rate capabilities, yield stresses, and failure strains of PP and PP/PE/PP separators are all enhanced remarkably by PDA modification. Thermal shrinkage results show that thermal stabilities and the shrinkage percentage of PDA-modified separators are improved. The electrochemical testing results conclude that the discharging capacities of PP (increased by 3.77%~187.57%) and PP/PE/PP (increased by 2.31%~92.21%) separators increase remarkably from 0.1 C to 5.0 C. The ionic conductivities of PDA-modified PP and PP/PE/PP separators are 1.5 times and 6.1 times higher than that of unmodified PP and PP/PE/PP separators, which in turn increase the electrolyte uptake and ionic migration. In addition, mechanical properties of PP (yield stresses: 17.48%~100.11%; failure stresses: 13.45%~82.71%; failure strains: 4.08%~303.13%) and PP/PE/PP (yield stresses: 11.77%~296.00%; failure stresses: 12.50%~248.30%; failure strains: 16.53%~32.56%) separators are increased greatly.

scholarly journals The Effect of Different Ratios of Malonic Acid to Plyvinylalcohol on Electrochemical and Mechanical Properties of Polyacrylonitrile Electrospun Separators in Lithium-Ion Batteries

2021 ◽  
Author(s):  
Fartash Khodaverdi ◽  
Mehran Javanbakht ◽  
Ali Vaziri ◽  
Mehdi Jahanfar
Keyword(s):  
Lithium Ion Batteries ◽  
Malonic Acid ◽  
Lithium Ion ◽  
Thermal Shrinkage ◽  
Performance Tests ◽  
Optimum Ratio ◽  
A Value ◽  
Electrolyte Uptake ◽  
Hydrophilic Materials ◽  
Modified Separator

The present study aimed to investigate the mechanical, thermal, and electrochemical properties of Polyacrylonitrile (PAN) electrospun separators in the presence of Polyvinylalcohol (PVA) hydrophilic materials and Malonic Acid (MA) crosslinker inside the lithium-ion batteries. The results showed that the M3 modified separator with the MA to PVA+MA (wt./wt.) optimum ratio of 37.5 % had the best performance in all tests. This separator had a value of 3.16 mS/cm in the ion conductivity test. Additionally, it had an electrolyte uptake of 1172 % (2.39 times more than the neat PAN separator) and thermal shrinkage of 7.4 % at 180 °C, where this value was 14.5 % for neat PAN separator at the same experimental condition. Furthermore, the acceptable performance in the battery performance tests was compared with other separators.

scholarly journals Multilayered PVDF-HFP Porous Separator via Phase Separation and Selective Solvent Etching for High Voltage Lithium-Ion Batteries

Membranes ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 41
Author(s):  
Van-Tien Bui ◽  
Van-Toan Nguyen ◽  
Ngoc-Anh Nguyen ◽  
Reddicherla Umapathi ◽  
Liudmila L. Larina ◽  
...  
Keyword(s):  
Phase Separation ◽  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Vinylidene Fluoride ◽  
Lithium Ion ◽  
High Energy ◽  
Selective Solvent ◽  
Energy Storage Devices ◽  
Electrolyte Uptake ◽  
Highly Porous

The development of highly porous and thin separator is a great challenge for lithium-ion batteries (LIBs). However, the inevitable safety issues always caused by poor mechanical integrity and internal short circuits of the thin separator must be addressed before this type of separator can be applied to lithium-ion batteries. Here, we developed a novel multilayer poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) membrane with a highly porous and lamellar structure, through a combination of evaporation-induced phase separation and selective solvent etching methods. The developed membrane is capable of a greater amount of electrolyte uptake and excellent electrolyte retention resulting from its superior electrolyte wettability and highly porous structure, thereby offering better electrochemical performance compared to that of a commercial polyolefin separator (Celgard). Moreover, benefiting from the layered configuration, the tensile strength of the membrane can reach 13.5 MPa, which is close to the mechanical strength of the Celgard type along the transversal direction. The elaborate design of the multilayered structure allows the fabrication of a new class of thin separators with significant improvements in the mechanical and electrochemical performance. Given safer operation, the developed multilayer membrane may become a preferable separator required for high-power and high-energy storage devices.

Composite Nanofiber Membrane for Lithium-Ion Batteries Prepared by Electrostatic Spun/Spray Deposition

2016 ◽  
Vol 13 (1) ◽  
Author(s):  
Bin Yu ◽  
Xiao-Ming Zhao ◽  
Xiao-Ning Jiao ◽  
Dong-Yue Qi
Keyword(s):  
Lithium Ion Batteries ◽  
Vinylidene Fluoride ◽  
Spray Deposition ◽  
Lithium Ion ◽  
Cycle Performance ◽  
Thermal Shrinkage ◽  
Electrostatic Spray Deposition ◽  
Electrolyte Uptake ◽  
Poly Vinylidene Fluoride ◽  
Electrostatic Spray

A new kind of sandwiched composite membrane (SCM) for lithium-ion batteries is prepared by depositing zirconia microparticle between two layers of electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) nanofibers by electrostatic spray deposition. The thermal shrinkage, electrochemical properties of the separator, and cycle performance for batteries with the SCM were investigated. The results show that the SCM has a high electrolyte uptake and easily absorbs electrolyte to form gelled polymer electrolytes (GPEs). The SCM GPEs have a high ionic conductivity of up to 2.06 × 10−3 S cm−1 at room temperature and show a high electrochemical stability potential of 5.4 V. With LiCoCO2 as cathode, the cell with SCM GPEs exhibits a high initial discharge capacity of 149.7 mAh g−1.

scholarly journals High Temperature Resistant Separator of PVDF-HFP/DBP/C-TiO2 for Lithium-Ion Batteries

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2813 ◽  
Author(s):  
Haijuan Li ◽  
Ling Li ◽  
Shuaizhi Zheng ◽  
Xinming Wang ◽  
Zengsheng Ma
Keyword(s):  
Titanium Dioxide ◽  
Ionic Conductivity ◽  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Room Temperature ◽  
Lithium Ion ◽  
Inversion Method ◽  
Tio2 Nanofibers ◽  
Electrolyte Uptake ◽  
Composite Separator

To improve the thermal shrinkage and ionic conductivity of the separator for lithium-ion batteries, adding carboxylic titanium dioxide nanofiber materials into the matrix is proposed as an effective strategy. In this regard, a poly(vinylidene fluoride-hexafluoro propylene)/dibutyl phthalate/carboxylic titanium dioxide (PVDF-HFP/DBP/C-TiO2) composite separator is prepared with the phase inversion method. When the content of TiO2 nanofibers reaches 5%, the electrochemical performance of the battery and ion conductivity of the separator are optimal. The PVDF-HFP/DBP/C-TiO2 (5%) composite separator shows about 55.5% of porosity and 277.9% of electrolyte uptake. The PVDF-HFP/DBP/C-TiO2 (5%) composite separator has a superior ionic conductivity of 1.26 × 10 −3 S cm−1 and lower interface impedance at room temperature, which brings about better cycle and rate performance. In addition, the cell assembled with a PVDF-HFP/DBP/C-TiO2 separator can be charged or discharged normally and has an outstanding discharge capacity of about 150 mAh g−1 at 110 °C. The battery assembled with the PVDF-HFP/DBP/C-TiO2 composite separator exhibits excellent electrochemical performance under high and room temperature environments.

Effect of additives on wettability, thermal stability and electrochemical properties of γ-Al2O3-coating separator for lithium-ion batteries

2021 ◽  
pp. 1-15
Author(s):  
Ji Yan ◽  
Zhen Li ◽  
Min-Yun Wang ◽  
Kezheng Gao ◽  
Yong Zhang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Electrochemical Properties ◽  
Lithium Ion Batteries ◽  
Lithium Ion ◽  
Thermal Shrinkage ◽  
Al2o3 Coating ◽  
Effect Of Additives ◽  
Electrolyte Uptake ◽  
Superior Cycling Stability ◽  
Battery Application

Abstract Physical properties of separator, as important parameters in affecting electrochemical performance and safety of lithium ion batteries, should be paid more attention. In this study, three kinds of surfactants and dispersants were adopted to investigate their effects on thermal stability, wettability and electrochemical properties of γ-Al2O3 coating polyethylene-based separator. The experimental results showed that with the synergistic helpfulness of PEG-2000 as surfactant and D-067 as dispersant, γ-Al2O3 coating polyethylene separator demonstrates superior thermal stability (no significant thermal shrinkage after heating at 120°C), electrolyte uptake ability and improved wettability (contact angle of 27.9°). Based on further testing results in Li//MCMB coin cells, the cell with γ-Al2O3 coating polyethylene separator exhibits higher capacity and superior cycling stability than other two bare counterparts separators at room temperature after 200 cycles. These results demonstrate that the as-prepared separator is highly promising for lithium ion battery application with the help of suitable surfactant and dispersant.

Synthesis and Electrochemical Performance of SnO2/Graphene Anode Material for Lithium Ion Batteries

2013 ◽  
Vol 28 (5) ◽  
pp. 515-520 ◽  
Author(s):  
Zhen-Jun YU ◽  
Yan-Li WANG ◽  
Hong-Gui DENG ◽  
Liang ZHAN ◽  
Guang-Zhi YANG ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Anode Material ◽  
Lithium Ion
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