A Flexible and Safe Planar Zinc-Ion Micro-Battery with Ultrahigh Energy Density Enabled by Interfacial Engineering for Wearable Sensing Systems

摘要

Aqueous zinc-ion micro-batteries (ZIMBs) have attracted considerable attentionowing to their reliable safety, low cost, and great potential for wearabledevices. However, current ZIMBs still suffer from various critical issues,including short cycle life, poor mechanical stability, and inadequate energydensity. Herein, the fabrication of flexible planar ZIMBs with ultrahigh energydensity by interfacial engineering in the screen-printing process based on highperformanceMnO_2-based cathode materials is reported. The Ce-doped MnO_2(Ce-MnO_2) exhibits significantly enhanced capacity (389.3 mAh g~(?1)), considerablerate capability and admirable cycling stability than that of the pureMnO2. Importantly, the fabrication of micro-electrodes with ultrahigh massloading of Ce-MnO_2 (24.12 mg cm~(?2)) and good mechanical stability is achievedthrough optimizing the interfacial bonding between different printed layers.The fabricated planar ZIMBs achieve a record high capacity (7.21 mAh cm~(?2) or497.31 mAh cm~(?3)) and energy density (8.43 mWh cm~(?2) or 573.45 mWh cm~(?3)),as well as excellent flexibility. Besides, a wearable self-powered sensing systemfor environmental monitoring is further demonstrated by integrating the planarZIMBs with flexible solar cells and a multifunctional sensor array. This worksheds light on the development of high-performance planar ZIMBs for futureself-powered and eco-friendly smart wearable electronics.