Kirigami-based stretchable lithium- ion batteries

Zeming Song1,*, Xu Wang1,*, Cheng Lv1, Yonghao An1, Mengbing Liang4, Teng Ma1, David He1,2, Ying-Jie Zheng3, Shi-Qing Huang3, Hongyu Yu4,5 & Hanqing Jiang1

Energy storage devices, such as supercapacitors and lithium-ion batteries (LIBs) that are able to sustain large strains (much greater than 1%) under complex deformations (for instance, bending, tension/com- pression, and torsion) are indispensable components for exible, stretchable electronics, and recently emerging wearable electronics, such as exible displays1–4, stretchable circuits5, hemispherical electronic eyes6, and epidermal electronics7. Various approaches have been employed to achieve exible and stretch- able energy storage devices, such as thin lm based bendable supercapacitors8–11 and batteries10,12–16, buckling-based stretchable supercapacitors17,18, and island-serpentine-based stretchable LIBs19. Recently, an origami-based approach was adopted to develop highly foldable LIBs, where standard LIBs were pro- duced followed by designated origami folding20. e folding endows the origami LIB with a high level of foldability by changing the LIB from a planar state to a folded state. However, the previously developed origami-based foldable devices20,21 have two disadvantages. First, their foldability is limited from the folded state to the planar state. Although it can be tuned by di erent folding patterns, the same constraint is still prescribed by the planar state. Second, the folded state involves uneven surfaces, which introduces inconvenience when integrating with planar systems, though this issue can be somewhat circumvented. e approach introduced here combines folding and cutting, by the name of kirigami, to de ne patterns that form an even surface a er stretching and the stretchability is not limited by the planar state. e folding and cutting lead to high level of stretchability through a new mechanism, “plastic rolling”, which has not yet been discovered and utilized in the stretchable electronics/systems. e LIBs were produced by the standard slurry coating (using graphite as an anode and LiCoO2 as a cathode) and packaging pro- cedure, followed by a designated folding and cutting procedure to achieve a particular kirigami pattern. Kirigami batteries are also compatible with emerging battery fabrication skills such as direct printing or painting22. Following kirigami patterns, the printed or painted kirigami batteries is expected to perform similarly as batteries fabricated in conventional way. Over 150% stretchability has been achieved and the produced kirigami LIBs have demonstrated the ability to power a Samsung Gear 2 smart watch, which shows the potential applications of this approach. e kirigami-based methodology can be readily expanded to other applications to develop highly stretchable devices and thus deeply and broadly impact the eld of stretchable and wearable electronics.