Advances in smart textiles and biomedical implants require stretchable batteries. A new study proposes a novel design for the fabrication and characterization of stretchable-sliding batteries.

Kelly et al. developed a lithium ion battery with a stretchable polymer electrolyte sandwiched between two pairs of sliding electrodes – a pair of lithium iron phosphate electrodes acting as the cathode, and a pair of graphite electrodes as the anode.

The polymer electrolyte film used in the battery is made of a polyethylene oxide blend chosen to optimize and enhance mechanical and electrochemical characteristics including ion conductivity, elastic modulus and tensile strength. The battery’s layered configuration allows the electrolyte layer to bend and stretch, and the electrodes to slide against each other. This flexibility increases the contact area between the active cathode layer and the electrolyte when stretched.

The researchers studied the battery’s impedance and its behavior under deformation and thermal decomposition temperature. They discovered that as the battery undergoes strain within its elastic region, its capacity and conductivity increase until it reaches a critical level of strain, where its performance begins to degrade. According to the authors, properties of the battery can be fine-tuned to meet specific requirements for potential future applications and commercialization.

Though the study focused on specific molecular weight blended polymers, author Haleh Ardebili noted that the characterization method through sliding electrode setup can be extended to the examination of other polymers. “The sliding-stretchable battery serves as an experimental platform for in situ strain-dependent electrochemical characterization of the solid polymer electrolyte,” she said. “This application is useful for the investigation of solid polymers and their interfacial properties during stretching.”

Source:In situ strain dependent electrochemical characterization of a stretchable-sliding battery,” by T. Kelly, A. Vu, M. Yuan, M. Kammoun, and H. Ardebili, AIP Advances (2019). The article can be accessed at https://doi.org/10.1063/1.5111557.