Dependence of Linker Length and Composition on Ionic Conductivity and Lithium Deposition in Single-Ion Conducting Network Polymers
- Univ. of California, Berkeley, CA (United States)
- Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
In this report, single-ion conducting electrolytes stand as promising alternatives to state-of-the-Art electrolytes in lithium batteries, although a single-ion conducting material with high Li+ conductivity, stability in contact with lithium, and suitable mechanical properties has been slow to emerge. Here, we describe the synthesis of a series of single-ion conducting network polymers from the reaction of tetrakis(4-(chloromethyl)-2,3,5,6-Tetrafluorophenyl)borate with oligoethylene glycoxide linkers Li2O[(CH2CH2)O]n (n = 1, 2, 3, 9, and 22). Polymers with the longest linkers (n = 9 and 22; ANP-9 and ANP-10, respectively) form materials with conductivities of ~ 10-6 S cm-1 at 100 °C. With the addition of 65 wt % propylene carbonate (PC), all the network polymers in the series exhibit high conductivities at ambient temperatures, with the n = 1 material (ANP-6) achieving a bulk ionic conductivity of 2.5 x 10-4 S cm-1 at 25 °C. More conductive single-ion conducting gels could be prepared by using the less coordinating pentanediol dilithium salt as a linker (ANP-11; σ = 3.5 x 10-4 S cm-1 at 25 °C), although this material exhibited a surprisingly high interfacial resistance in contact with a lithium electrode. In contrast, the gel formed with ANP-6 is notably stable in contact with metallic lithium electrodes, displays a lithium-ion transference number of unity, and boasts a wide electrochemical stability window of greater than 4.5 V. Temperature-dependent ac impedance analysis reveals that the ionic conductivity of this material-and likely the other gels in the series-matches closely to a Vogel-Tamman-Fulcher temperature model.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC02-05CH11231
- OSTI ID:
- 1843007
- Journal Information:
- Macromolecules, Journal Name: Macromolecules Journal Issue: 16 Vol. 54; ISSN 0024-9297
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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