As soft electronic devices increasingly require stretchable, conformable batteries, safety concerns regarding the use of liquid electrolytes in lithium ion batteries (LIBs) arise. Unfortunately, the canonical tradeoff between mechanical strength and ionic conductivity in polymer electrolytes has forced most reported stretchable batteries to incorporate mechanically weak electrolytes containing flammable liquids within strain engineered structures. Herein, we introduce a supramolecular design as a novel strategy to decouple ionic conductivity from mechanical strength in polymer electrolytes. The supramolecular lithium ion conductor (SLIC) utilizes orthogonally functional H-bonding domains and ion conducting domains to create a polymer electrolyte with high resilience (4.9 MJ m-3) and high ionic conductivity (1.2*10-4 S cm-1 at 25° C ). Implementation of SLIC as a binder material allows for the creation of stretchable Li-ion battery electrodes with strain capability of over 900% via a conventional slurry process. The supramolecular binding between SLIC-based battery components enables the fabrication of the first intrinsically stretchable LIB. The SLIC battery has a capacity of 1.1 mAh cm-2, an operating voltage of 1.8 V, and functions even when stretched to 70% of its original length. The method reported here of decoupling ionic conductivity from mechanical properties opens a new route to create highly resilient ion transport materials for energy storage applications.

Decoupling of mechanical properties and ionic conductivity in supramolecular stretchable battery materials

2019 Fall National Meeting

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