Hydrogel Electrolyte for Reliable Flexible Zinc Ion Battery

Description

  [Demand for flexible batteries]   Rapidly developing wearable electronic devices demand reliable, flexible batteries to power them. The market for flexible batteries was valued at US$69.6 million in 2015 and is estimated to be worth US$958.4 million by 2022 (MarketsandMarkets). Clearly, in the near future, flexible batteries, along with the flexible systems they power, will vastly promote the informatization of personal lives on such aspects as real-time health monitoring and sports and sleep data provision.   [Flexible lithium ion batteries are not sufficiently safe and reliable]   Considering that flexible batteries are exposed to many unpredictable mechanical impacts, ensuring their safety and reliability is a considerable challenge. Such batteries rely on not only flexibility, but also the stretchability and self-healability of a device. Lithium ion batteries (LIBs) have dominated the market. However, LIBs adopt organic electrolytes, which cause various reliability and safety problems. Therefore, achieving reliable and flexible LIBs is still impractical.   [Extremely safe rechargeable zinc ion batteries]                                         Research on rechargeable zinc ion batteries (ZIBs) has extensively progressed recently. ZIBs are characterized by high capacity, low cost, eco-friendliness, and easy fabrication. Furthermore, as aqueous electrolyte batteries, ZIBs are intrinsically safe, even when exposed to harsh environments including various mechanical impacts. This feature renders them suitable for flexibilization.   [Problem: Lack of high-performance solid-state electrolytes for reliable and flexible ZIBs]   Most of the existing ZIBs adopt liquid solution electrolytes; nevertheless, assembling flexible devices with a liquid solution is not feasible. The development of reliable and flexible ZIBs is currently impeded by a lack of high-performance solid-state electrolytes. Polymer gels are commonly adopted solid-state electrolytes; however, most polymers possess a low tolerance to zinc salts. When used as hosts, polymer gels exhibit low Zn2+ionic conductivity, reducing the capacity and cycling stability of flexible ZIBs, in addition to their reliability.   [Hydrogel-based solid-state electrolytes for reliable and flexible ZIBs to be developed in this project]   In this project, we intend to execute the following processes: We will screen hydrogels and modify the selected ones through grafting and composite fabrication to enhance their electrochemical performance. We will use the modified hydrogel to fabricate rechargeable flexible ZIBs with high capacity and superior cycling stability.To enhance reliability, we will introduce a dual-crosslinking mechanism to the hydrogel electrolytes to enhance their modulus, stretchability, and self-healability. Consequently, we will develop stretchable, self-healable ZIBs with high reliability.