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Irene Lau1 Michael Pope1

1, University of Waterloo, Waterloo, Ontario, Canada

Emerging technologies are becoming increasingly advanced, requiring flexible components and their integration into various miniaturized interfaces such as for rollable displays, wearable technologies and e-textiles. As a result, there is a need for a fully flexible battery with high energy storage capacity that is simple and cost effective. In this work we demonstrate a simple route to producing flexible lithium-sulfur batteries. An adaptation to the well-established laser-scribing method to convert commercial polymer films into a patterned graphene-like electrode is used. The laser-induced graphene cathode and anode are patterned sequentially to create a 2D interdigitated structure. We show that, after the first laser pass, sulfur can be deposited selectively on the electrode through heterogeneous nucleation followed by melt imbibition. The other set of electrodes fingers are scribed to form the anode, followed by a deposition of silver nanoparticles to be used as seeds for lithium nucleation. A reverse pulse plating technique is adopted for the deposition of a smooth, dendrite-free lithium anode at a relatively high current density of 1 mA/cm2. Lastly, an ionogel with a polysulfide-scavenger is applied onto the electrode fingers for the completion of a fully flexible device containing an electrolyte matrix rich with polar groups to capture and prevent the migration of polysulfides to the anode in order to maximize capacity retention over the life of the cell. Preliminary work shows that the novel method of sulfur deposition can yield uniform films of over the entire electrode and obtaining practical loadings of up to 3 mg/cm2. Initial cycling shows that the battery can achieve an energy density as high as 196.9 mWh/cm3, which exceeds that of most published reports on lithium-ion microbatteries produced through nano-templating and microfabrication techniques.

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