Wearable and Fully Biocompatible All-in-One Structured ″Paper-Like″ Zinc Ion Battery

A power supply with the characteristics of portability and safety will be one of the dominating mainstreams for future wearable electronics and implantable biomedical devices. The conventional energy storage devices with typical sandwich structures have complicated components and low mechanical properties, suffering from the apparent performance degradation during deformation and hindering the possibility of implanting biomedical units. Herein, a novel all-in-one structure ″paper-like″ zinc ion battery (ZIB) was designed and assembled from an electrospun polyacrylonitrile (PAN) nanomembrane (as the separator) with in situ deposited anode (zinc nanosheets) and cathode (MnO₂ nanosheets), which ensures the monolith under different bending states by avoiding the relative sliding and detaching between the integrated layers. Benefiting from the well-designed all-in-one construction and electrodes, the resultant all-in-one ZIB (AZIB) features an ultrathin thickness (about 97 μm), superior specific capacity of 353.8 mAh g^-1 (at 0.1 mA cm^-2), and outstanding cycling stability (98.7% capacity retention after 500 cycles at 1 A cm^-2). And the achieved volumetric energy density is as high as 17.5 mWh cm^-3 at a power density of 116.4 mW cm^-3. Impressively, the concept of wearable electronic applications of the obtained AZIB was fully demonstrated with excellent flexibility and remarkable temperature resistance under various severe conditions. Our AZIB may provide a versatile strategy for applying and developing flexible wearable electronics and implantable biomedical devices.