Five approaches for the synthesis of polyelectrolytes towards solid-state, safe and high performing Li batteries

Abstract:

In last decade, intensive efforts focused on flexible, lightweight and safe energy storage devices have been stimulated by the increased demands of next-generation portable and flexible electronics, wearable devices and electric cars. The development of safe, efficient solid-state lithium batteries requires polymer electrolytes with high ionic conductivity (>10-4 S cm-1 at 25 °C) as well as good electrochemical and thermal stabilities. Among promising candidates, a new class of polyelectrolytes, namely polymeric analogs of ionic liquids, a.k.a. poly(ionic liquid)s (PILs), has recently gained significant attention. PILs can be considered as the macromolecular analogs of ionic liquids (ILs), in the best cases combining the advantages of polymers (viscoelasticity, processability, film-forming properties, etc.) and ILs (high thermal and electrochemical stabilities, enhanced ionic conductivity, etc.). In this work, five approaches for the preparation of novel PILs or “polymeric single-ion conductors” and their testing in Li batteries will be presented. Synthesized PILs differed by their macro architecture (random and block copolymers) and were tested as solid polyelectrolytes in Li/PIL/LiFePO4 batteries. Assembled cells were working at 25-70 °C, delivering large capacities (up to 130 mAh/g) and showing capability to reversibly operate at relatively high rates (up to C/5).

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