Fully Integrated Design of a Stretchable Solid-State Lithium-Ion Full Battery

A solid-state lithium-ion battery, in which all components (current collector, anode and cathode, electrolyte, and packaging) are stretchable, is introduced, giving rise to a battery design with mechanical properties that are compliant with flexible electronic devices and elastic wearable systems. By depositing Ag microflakes as a conductive layer on a stretchable carbon-polymer composite, a current collector with a low sheet resistance of approximate to 2.7 omega (-1) at 100% strain is obtained. Stretchable electrodes are fabricated by integrating active materials with the elastic current collector. A polyacrylamide-water-in-salt electrolyte is developed, offering high ionic conductivity of 10(-3) to 10(-2) S cm(-1) at room temperature and outstanding stretchability up to approximate to 300% of its original length. Finally, all these components are assembled into a solid-state lithium-ion full cell in thin-film configuration. Thanks to the deformable individual components, the full cell functions when stretched, bent, or even twisted. For example, after stretching the battery to 50%, a reversible capacity of 28 mAh g(-1) and an average energy density of 20 Wh kg(-1) can still be obtained after 50 cycles at 120 mA g(-1), confirming the functionality of the battery under extreme mechanical stress.