Preparation of porous fluorinated polyimide separator for lithium-ion batteries by non-solvent induced phase separation process

2021 ◽  
pp. 095400832098815
Author(s):  
Yake Shi ◽  
Biao Yuan ◽  
Yanzhen He ◽  
Cuijia Duan ◽  
Shuo Yan ◽  
...  
Keyword(s):  
Phase Separation ◽  
Lithium Ion Batteries ◽  
High Performance ◽  
Retention Rate ◽  
Lithium Ion ◽  
Promising Candidate ◽  
Fluorinated Polyimide ◽  
Electrolyte Uptake ◽  
Phase Separation Process ◽  
Interconnected Structure

A series of novel porous fluorinated polyimide (FPI) separators containing trifluoromethyl group (–CF3) were prepared by the non-solvent induced phase separation (NIPS) strategy. The prepared FPI separator with 60% molar content (fluorinated dianhydride: non-fluorinated dianhydride: diamine = 60: 40: 100) of fluorinated groups (FPI-60%) could stably exist in the electrolyte as a LIBs separator. The resultant FPI-60% separator possesses high thermal stability with the Tg of 289.4°C and exhibits no shrinkage even at 200°C. The morphologies of the FPI-60% separators were adjusted by introducing small molecular non-solvent additives-ethanol, and the FPI-60% separators present the spongy-like and interconnected structure with different porosity as the amount of ethanol changed from 1 wt% to 10 wt%. The FPI-60% separators display excellent electrolyte uptake with 170%–200% and the ionic conductive could reach 1.17 mS/cm which is four times approximately than that of the PP separator. The lithium-ion batteries (LIBs) using FPI-60% separators with 10 wt% ethanol added show better rate capacities (102.8 mAh/g, 70.8 mAh/g of PI-10 and PP separator at 2 C, respectively) and the capacity retention rate is 93.2% after 50 cycles. The results prove that the porous FPI separator is a promising candidate for high-performance LIBs.

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.

PEI-SiO2 composite membranes with high thermal stability: Synthesis by self-assembled in situ growth and application in lithium-ion batteries

2020 ◽  
pp. 095400832096455
Author(s):  
Wei Song ◽  
Weiwei Cui ◽  
Xu Wang ◽  
Zeyu Lin ◽  
Wei Deng ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Lithium Ion Batteries ◽  
Composite Membrane ◽  
Retention Rate ◽  
Lithium Ion ◽  
Composite Membranes ◽  
High Porosity ◽  
Electrolyte Uptake ◽  
Electrochemical Window

To improve the safety of lithium-ion batteries (LIBs), a polyether amide–silica (PEI-SiO2) composite membrane was developed by the in situ hydrolysis of tetraethylorthosilicate (TEOS) and its subsequent self-assembly on the surface of PEI fibers. Because of the presence of the SiO2 shell, the PEI-SiO2 composite membrane exhibited good thermal stability at high temperatures. The composite membrane did not change its color and size after heating at 200°C for 1 h as well as exhibited excellent flame retardancy. Moreover, the membrane maintained its high porosity even after the introduction of shell layers. The electrolyte is completely absorbed in the membrane within 0.5 s. The electrolyte uptake was up to 625%, and the ionic conductivity was up to 1.9 mS/cm at room temperature. Compared to the polyolefin membrane and the pure PEI membrane, the PEI-SiO2 composite membrane showed higher electrochemical stability, with an electrochemical window of up to 5.5 V. The battery assembled with the composite membrane showed excellent cycle stability, and the capacity retention rate was as high as 98.6% after 50 cycles. The LIBs based on the PEI-SiO2 composite membrane exhibited safe operation and high electrochemical performance, thus highlighting the applicability of the composite membrane in high-power batteries.

scholarly journals Aggregation-Morphology-Dependent Electrochemical Performance of Co3O4 Anode Materials for Lithium-Ion Batteries

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3149 ◽  
Author(s):  
Linglong Kong ◽  
Lu Wang ◽  
Deye Sun ◽  
Su Meng ◽  
Dandan Xu ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Anode Materials ◽  
High Performance ◽  
Retention Rate ◽  
Lithium Ion ◽  
Charge Transfer Resistance ◽  
Superior Performance ◽  
Electrode Structure ◽  
Transfer Resistance

The aggregation morphology of anode materials plays a vital role in achieving high performance lithium-ion batteries. Herein, Co3O4 anode materials with different aggregation morphologies were successfully prepared by modulating the morphology of precursors with different cobalt sources by the mild coprecipitation method. The fabricated Co3O4 can be flower-like, spherical, irregular, and urchin-like. Detailed investigation on the electrochemical performance demonstrated that flower-like Co3O4 consisting of nanorods exhibited superior performance. The reversible capacity maintained 910.7 mAh·g−1 at 500 mA·g−1 and 717 mAh·g−1 at 1000 mA·g−1 after 500 cycles. The cyclic stability was greatly enhanced, with a capacity retention rate of 92.7% at 500 mA·g−1 and 78.27% at 1000 mA·g−1 after 500 cycles. Electrochemical performance in long-term storage and high temperature conditions was still excellent. The unique aggregation morphology of flower-like Co3O4 yielded a reduction of charge-transfer resistance and stabilization of electrode structure compared with other aggregation morphologies.

Fluorinated polyimide with sulfonyl group as a novel binder for high-performance lithium-ion batteries

Ionics ◽  
2021 ◽  
Vol 27 (4) ◽  
pp. 1579-1588
Author(s):  
Zuyan Liu ◽  
Linxin Yao ◽  
Jiqing Hu ◽  
Zhiming Qiu ◽  
Yurong Yan
Keyword(s):  
Lithium Ion Batteries ◽  
High Performance ◽  
Lithium Ion ◽  
Sulfonyl Group ◽  
Fluorinated Polyimide

Robust fluorinated polyimide nanofibers membrane for high-performance lithium-ion batteries

2018 ◽  
Vol 549 ◽  
pp. 321-331 ◽  
Author(s):  
Lingyi Kong ◽  
Yurong Yan ◽  
Zhiming Qiu ◽  
Zhiqiang Zhou ◽  
Jiqing Hu
Keyword(s):  
Lithium Ion Batteries ◽  
High Performance ◽  
Lithium Ion ◽  
Fluorinated Polyimide

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.

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