Affiliation:
1. University of Münster MEET Battery Research Center Institute of Physical Chemistry Corrensstraße 46 48149 Münster Germany
2. Laboratory of Organic and Macromolecular Chemistry (IOMC) Friedrich Schiller University Jena Humboldtstr. 10 07743 Jena Germany
3. Center for Energy and Environmental Chemistry Jena (CEEC Jena) Friedrich Schiller University Jena Philosophenweg 7a 07743 Jena Germany
4. Helmholtz-Institut Münster, IEK-12, Forschungszentrum Jülich GmbH Corrensstraße 46 48149 Münster Germany
Abstract
AbstractDual‐ion batteries (DIBs) represent a promising alternative for lithium ion batteries (LIBs) for various niche applications. DIBs with polymer‐based active materials, here poly(2,2,6,6‐tetramethylpiperidinyl‐N‐oxyl methacrylate) (PTMA), are of particular interest for high power applications, though they require appropriate electrolyte formulations. As the anion mobility plays a crucial role in transport kinetics, Li salts are varied using the well‐dissociating solvent γ‐butyrolactone (GBL). Lithium difluoro(oxalate)borate (LiDFOB) and lithium bis(oxalate)borate (LiBOB) improve cycle life in PTMA||Li metal cells compared to other Li salts and a LiPF6‐ and carbonate‐based reference electrolyte, even at specific currents of 1.0 A g−1 (≈10C), whereas LiDFOB reveals a superior rate performance, i. e., ≈90 % capacity even at 5.0 A g−1 (≈50C). This is attributed to faster charge‐transfer/mass transport, enhanced pseudo‐capacitive contributions during the de‐/insertion of the anions into the PTMA electrode and to lower overpotentials at the Li metal electrode.