Polymer electrolytes for safe Lithium ion, electrochromic and photovoltaic applications

Polymer electrolytes represent the ultimate in terms of desirable properties for Li-ion batteries, but also other applications as electrochomic devices, lithium air and photovoltaic cells. They can offer an all-solid-state construction, a wide variety of shapes and sizes, light-weight, low-cost of fabrication, high safety and a higher energy density. The use of the polymer electrolyte with the same basic composition can simplify the production of devices for end users and can get the possibility to produce cointegrated devices when needed. Here, we describe the use and the electrochemical characterization of gel-polymer and all solid state membranes based on methacrylates and polyethene oxides produced both by UV curing technique and by thermopolymerization and their application in Lithium ion cells, flexible electrochromic devices and PV cells. The ionic conductivity of the studied membranes showed good ionic conductivity values in the order of 10-3 Scm-1 at room temperature and the anodic breakdown voltage higher than 4.5 V vs. Li. Due to the production method, an high electrode-electrolyte interface can be obtained leading to high electrochemical performance, e.g long cyclability, high C rates, and simple scalability for industrial applications. By this method we are able to produce flexible, transparent films of varying thickness in less than 5min, and the whole process for production of polymer membranes from minutes to less than 1 h. All processes are very versatile and easily permits to change the polymer composition.