Impact of Ionic Liquid on Lithium Ion Battery with a Solid Poly(Ionic Liquid) Pentablock Terpolymer as Electrolyte and Separator

Journal Article · Tue Nov 17 00:00:00 EST 2020 · Polymer

DOI:https://doi.org/10.1016/j.polymer.2020.122975· OSTI ID:1735937

Chen, Tzu-Ling ^[1]; Sun, Rui ^[1]; Willis, Carl ^[2]; Krutzer, Bert ^[3]; Morgan, Brian ^[4]; Beyer, Fredrick L. ^[4]; Han, Kee Sung ^[5]; Murugesan, Vijayakumar  ^[5]; Elabd, Yossef A. ^[1]

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1. Texas A & M University
2. Kraton Polymers
3. Kraton Polymers, LLC
4. U.S. Army Research Laboratory
5. BATTELLE (PACIFIC NW LAB)

In this work, a ternary blend solid polymer electrolyte (SPE) consisting of a poly(ionic liquid) (PIL) multiblock polymer, lithium salt, and ionic liquid (IL) was investigated with the goal of understanding the influence of IL concentration on ion transport mechanisms and electrochemical stability. The physical, transport, mechanical, morphological, and electrochemical properties of the ternary blend SPE were systematically investigated as a function of IL concentration (r = [IL]/[PIL] mole ratio between 0.1 and 0.7). The results indicate that with increasing IL concentration, the continuous conductive domain increases along with the polymer chain segmental mobility, as well as facilitate ionic conductivity, while the mechanical modulus exhibits a percolation threshold (from 52.17 MPa to 0.55 MPa at r = 0.2 to 0.3). Surprisingly, at higher IL concentrations, there is a reduction in the lithium cation mobility (i.e., 9.3 × 10-12 m2 s-1 versus 3.8 × 10-12 m2 s-1 for r = 0.2 versus r = 0.5, respectively) as evidenced by pulsed-field gradient nuclear magnetic resonance (PFG-NMR), which coincides with an increased overpotential (i.e., 50 mV versus 150 mV for r = 0.2 versus r = 0.5, respectively) evidenced by lithium metal stripping and plating. This work provides valuable insights into the impact of IL on lithium ion conducting PIL block polymers, which may enable the design of new SPEs with both high ionic conductivity and improved stability for the future lithium ion batteries.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1735937
• Report Number(s): PNNL-SA-155312
• Journal Information: Polymer, Vol. 209
• Country of Publication: United States
• Language: English