Polymer-based solid electrolytes recently emerge as new reliable lithium ion battery materials by not only showing better safety (e.g., flammability and toxicity) over current state-of-the-art carbonate based liquid electrolytes. Especially when it comes to lithium metal, they offer sufficient mechanical stability to suppress dendrite formation and thus prevent thermal runaway reactions.1
Existing polymer based electrolytes suffer from low ionic conductivity – especially in the ambient temperature range - or poor redox stability against the electrode material. Self-assembled block-copolymers offer a new way to overcome these issues. Independent tuning of the unique components allows high ionic conductivity within one microdomain, while the inactive matrix ensures overall mechanical integrity.2
We prepared new high-performance solid block-copolymer/lithium salt hybrid electrolytes by molecular design of polymer structure, comprises high ionic conductivity at ambient temperature (10-3 S/cm @ 20°C), high lithium ion transference number and good redox stability within the scope (0 – 4 V against Li/Li+). We interpret the good performance of our polymer electrolyte by deciphering the hybrid structure with temperature dispersive in situ X-ray scattering studies from -15 to 105 °C.
1 Aurbach, D., Zinigrad, E., Cohen, Y. & Teller, H. A short review of failure mechanisms of lithium metal and lithiated graphite anodes in liquid electrolyte solutions. Solid State Ionics 148, 405-416 (2002).
2 Young, W. S., Kuan, W. F. & Epps, T. H. Block Copolymer Electrolytes for Rechargeable Lithium Batteries. J Polym Sci Pol Phys 52, 1-16 (2014).