Design and Construction of Cross-Linked PEO with the Integration of Helical Polyurethane as an Advanced All-Solid-State Polymer Electrolyte for Lithium Batteries

All-solid-state polymer electrolytes (SPEs) have been regarded as an advisible alternative for simultaneously overcoming the safety issues and high energy density demands presented in traditional lithium batteries, and they represent the development orientation of energy storage devices. This course describes the preparation of a cross-linked and helical polyurethane modified poly(ethylene oxide) (PEO@HPU) and its utilization as the SPE in lithium batteries, which can be used to teach upper-division undergraduates the principle of energy storage devices and the role of liquid-free electrolytes. Fourier transform infrared (FTIR) and 1H nuclear magnetic resonance (NMR) spectroscopies are used to determine the structure of the polymers. The ionic conductivity, lithium ion transference number, and electrochemical window of PEO@HPU are measured through an electrochemical workstation. The lithium batteries assembled by students are evaluated via a battery testing system. The modification by the special helical polymer obviously improves the electrochemical and battery performance of the PEO-based SPE. Upon completion of the experiment, students will understand the structure–activity relationship in materials science and propose new suggestions for designing advanced SPEs. This experiment requires well-prepared laboratory chemicals as well as long-term processes, so it is suitable to be considered as a project. Meanwhile, it can be also used for senior projects and interdisciplinary projects between engineering and science.