Preparation and Characterization of Thermoplastic Polyurethane-Based Polymer Electrolyte

Authors

Li Zhou, Chemistry and Chemical Engineering College, Anhui University, Hefei 230601, Anhui, China;Follow
Lie Wu, Chemistry and Chemical Engineering College, Anhui University, Hefei 230601, Anhui, China;
Zhao-Ming Xue, Chemistry and Chemical Engineering College, Anhui University, Hefei 230601, Anhui, China;

Corresponding Author

Li Zhou(863970772@qq.com)

Abstract

Electrolyte still has to be improved to satisfy the increasingly rigid demands of lithium ion batteries that have higher energy densities. Thermoplastic polyurethane (TPU) has two phase structures of soft segments and hard segments, which can guarantee the electrochemical and physical performances of electrolyte for lithium ion battery. It is now creatively applied to the gel polymer electrolyte matrix of lithium ion batteries. In this paper, a novel polymer membrane based on thermoplastic polyurethane/cellulose acetate (TPU/CA) was prepared by non-solvent induced phase separation (NIPS) method. Further, the TPU/CA blending gel polymer electrolyte (GPE) was prepared by absorbing liquid electrolyte. The effects of CA contents on the physical and electrochemical properties of the polymer membranes were studied. The structures, morphologies and performances of the membranes with different ratios of CA to TPU were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry (TG), differential scanning calorimetry (DSC), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The results show that the addition of CA to the blended polymer resulted in lower crystallinity of TPU and higher liquid uptake capability of electrolyte. The TPU/CA membrane possessed a large pore structure, but maintained sufficient mechanical strength. The decomposition temperature of TPU/CA samples with the weight loss of 5% was above 300℃, indicating good thermal stability of each sample. Among the TPU/CA blend electrolytes, the TPU/CA = 7/3 based electrolyte presented an ionic conductivity of 1.04 mS·cm^-1 with electrochemical stability above 5.1 V (vs. Li/Li⁺) at room temperature. The lithium ion battery with the TPU/CA = 7/3 GPE also exhibited a higher charge-discharge capacity of 150.9 mAh·g^-1 at 0.2 C, and a capacity retention rate of 95.7% at 0.5 C was confirmed after 100 cycles. All of these results demonstrate that this new TPU/CA blended gel polymer electrolyte is a promising candidate for lithium ion batteries.

Graphical Abstract

Keywords

lithium ion batteries, gel polymer electrolytes, non-solvent induced phase separation, thermoplastic polyurethane, cellulose acetate

DOI Link

https://doi.org/10.13208/j.electrochem.200606

Publication Date

2021-08-28

Online Available Date

2020-07-22

Revised Date

2020-06-28

Received Date

2020-06-06

Recommended Citation

Li Zhou, Lie Wu, Zhao-Ming Xue. Preparation and Characterization of Thermoplastic Polyurethane-Based Polymer Electrolyte[J]. Journal of Electrochemistry, 2021 , 27(4): 439-448.
DOI: Electrolyte still has to be improved to satisfy the increasingly rigid demands of lithium ion batteries that have higher energy densities. Thermoplastic polyurethane (TPU) has two phase structures of soft segments and hard segments, which can guarantee the electrochemical and physical performances of electrolyte for lithium ion battery. It is now creatively applied to the gel polymer electrolyte matrix of lithium ion batteries. In this paper, a novel polymer membrane based on thermoplastic polyurethane/cellulose acetate (TPU/CA) was prepared by non-solvent induced phase separation (NIPS) method. Further, the TPU/CA blending gel polymer electrolyte (GPE) was prepared by absorbing liquid electrolyte. The effects of CA contents on the physical and electrochemical properties of the polymer membranes were studied. The structures, morphologies and performances of the membranes with different ratios of CA to TPU were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry (TG), differential scanning calorimetry (DSC), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The results show that the addition of CA to the blended polymer resulted in lower crystallinity of TPU and higher liquid uptake capability of electrolyte. The TPU/CA membrane possessed a large pore structure, but maintained sufficient mechanical strength. The decomposition temperature of TPU/CA samples with the weight loss of 5% was above 300℃, indicating good thermal stability of each sample. Among the TPU/CA blend electrolytes, the TPU/CA = 7/3 based electrolyte presented an ionic conductivity of 1.04 mS·cm^-1 with electrochemical stability above 5.1 V (vs. Li/Li⁺) at room temperature. The lithium ion battery with the TPU/CA = 7/3 GPE also exhibited a higher charge-discharge capacity of 150.9 mAh·g^-1 at 0.2 C, and a capacity retention rate of 95.7% at 0.5 C was confirmed after 100 cycles. All of these results demonstrate that this new TPU/CA blended gel polymer electrolyte is a promising candidate for lithium ion batteries.

References

[1] Han J Y, Huang Y, Chen Y, Song A M, Deng X H, Liu B, Li X, Wang M S. High-performance gel polymer electrolyte based on chitosan-lignocellulose for lithium-ion batteries[J]. ChemElectroChem, 2020, 7(5): 1213-1224.
doi: 10.1002/celc.v7.5 URL

[2] Tian L L, Wang M K, Xiong L, Huang C, Guo H J, Yao S M, Zhang H R, Chen X D. Preparation and performance of p(OPal-MMA)/PVDF blend polymer membrane via phase-inversion process for lithium-ion batteries[J]. J. Electroanal. Chem., 2019, 839: 264-273.
doi: 10.1016/j.jelechem.2019.03.034 URL

[3] Gou J R, Liu W Y, Tang A M. A renewable and biodegradable nanocellulose-based gel polymer electrolyte for lithium-ion battery[J]. J. Mater. Sci., 2020, 55(24): 10699-10711.
doi: 10.1007/s10853-020-04667-7 URL

[4] Blomgren G E. The development and future of lithium ion batteries[J]. J. Electrochem. Soc., 2017, 164(1): A5019-A5025.
doi: 10.1149/2.0251701jes URL

[5] Jankowski S, Hiller M M, Fromm O, Winter M, Wiemhofer H D. Enhanced lithium-ion transport in polyphosphazene based gel polymer electrolytes[J]. Electrochim. Acta, 2015, 155: 364-371.
doi: 10.1016/j.electacta.2014.12.123 URL

[6] Wang T R, Zhang R Q, Wu Y M, Zhu G N, Hu C C, Wen J Y, Luo W. Engineering a flexible and mechanically strong composite electrolyte for solid-state lithium batteries[J]. J. Energy Chem., 2020, 46: 187-190.
doi: 10.1016/j.jechem.2019.10.010 URL

[7] Kuo P L, Tsao C H, Hsu C H, Chen S T, Hsu H M. A new strategy for preparing oligomeric ionic liquid gel polymer electrolytes for high-performance and nonflammable lithium ion batteries[J]. J. Membr. Sci., 2016, 499: 462-469.
doi: 10.1016/j.memsci.2015.11.007 URL

[8] Chai J C, Liu Z H, Zhang J J, Sun J R, Tian Z Y, Ji Y Y, Tang K, Zhou X H, Cui G L. A superior polymer electrolyte with rigid cyclic carbonate backbone for rechargeable lithium ion batteries[J]. ACS Appl. Mater. Interfaces, 2017, 9(21): 17897-17905.
doi: 10.1021/acsami.7b02844 URL

[9] Bhute M V, Kondawar S B. Electrospun poly(vinylidene fluoride)/cellulose acetate/AgTiO₂ nanofibers polymer ele-ctrolyte membrane for lithium ion battery[J]. Solid State Ionics, 2019, 333: 38-44.
doi: 10.1016/j.ssi.2019.01.019 URL

[10] Luo H F(罗化峰), Qiao Y D(乔元栋). Preparation and characterization of cellulose acetate-based separator for lithium-ion batteries[J]. J. Electrochem.(电化学), 2017, 23(4): 610-616.

[11] Tan L, Deng Y Y, Cao Q, Jing B, Wang X Y, Liu Y W. Gel electrolytes based on polyacrylonitrile/thermoplastic polyurethane/polystyrene for lithium-ion batteries[J]. Ionics, 2019, 25(8): 3673-3682.
doi: 10.1007/s11581-019-02940-7 URL

[12] Bao J J, Shi G J, Tao C, Wang C, Zhu C, Cheng L, Qian G, Chen C H. Polycarbonate-based polyurethane as a polymer electrolyte matrix for all-solid-state lithium batteries[J]. J. Power Sources, 2018, 389: 84-92.
doi: 10.1016/j.jpowsour.2018.04.020 URL

[13] Lavall R L, Ferrari S, Tomasi C, Marzantowicz M, Quartarone E, Fagnoni M, Mustarelli P, Saladino M L. MCM-41 silica effect on gel polymer electrolytes based on thermoplastic polyurethane[J]. Electrochim. Acta, 2012, 60: 359-365.
doi: 10.1016/j.electacta.2011.11.073 URL

[14] Chen B, Xu Q, Huang Z, Zhao Y R, Chen S J, Xu X X. One-pot preparation of new copolymer electrolytes with tunable network structure for all-solid-state lithium battery[J]. J. Power Sources, 2016, 331: 322-331.
doi: 10.1016/j.jpowsour.2016.09.063 URL

[15] Livazovic S, Li Z, Behzad A R, Peinemann K V, Nunes S P. Cellulose multilayer membranes manufacture with ionic liquid[J]. J. Membr. Sci., 2015, 490: 282-293.
doi: 10.1016/j.memsci.2015.05.009 URL

[16] Bolloli M, Antonelli C, Molmeret Y, Alloin F, Iojoiu C, Sanchez J Y. Nanocomposite poly(vynilidene fluoride)/nanocrystalline cellulose porous membranes as separators for lithium-ion batteries[J]. Electrochim. Acta, 2016, 214: 38-48.
doi: 10.1016/j.electacta.2016.08.020 URL