3R Batteries: Resilient, Repairable, and Recyclable Based on Liquid Gallium Electrode

Abstract

Billions of disposable thin‐film electronics will be produced annually in the near future, for applications in smart packaging, IoT, and wearable biomonitoring patches. For these cases, traditional rigid batteries are not optimal neither in terms of form and ergonomics nor ecological aspects. There is an urgent need for a new class of energy storage devices that are thin, stretchable, resilient, and recyclable. Herein, a novel architecture of materials and fabrication techniques is presented that permit a fully 3D printed soft‐matter thin‐film battery that is Resilient to mechanical strain, Repairable if cut, Rechargeable, and Recyclable at the end of its life. By taking advantage of a digitally printable ultra‐stretchable liquid metal‐based current collector and a novel Gallium‐Carbon anode electrode, the Ag2O‐Gallium battery is rapidly printed and customized per application. By optimizing the properties of the Gallium‐Carbon composite, a record‐breaking areal capacity of 26.37 mAh cm−2 is obtained, which improves after 10 cycles at 100% strain to 30.32 mAh cm−2, and an unprecedented maximum strain tolerance of ≈200%. Partially damaged batteries heal themselves. Severely damaged batteries are healed through innovative cold‐vapor stimulation. An example of a digitally printed, taylor‐made battery‐on‐the‐board health‐monitoring patch with printed sensors for monitoring the heart, and respiration is demonstrated.