Role of Additives for High Performance Polymer Electrolytes

Today, the progress of polymer electrolytes with high ambient ionic conductivity, better mechanical and thermal properties, has become the main objective in the field of polymer science because of their requirements in super capacitors, rechargeable batteries, fuel cells and other electrochemical devices. Many kinds of polymer electrolytes have been developed, however main drawback is the low ionic conductivity, which is inadequate for most of the device applications. Efforts have also been made to enhance the ionic conductivity of polymer electrolytes to meet the demand for different devices. Although polymer electrolytes with high value of ionic conductivity (∼10⁻³-10⁻⁴ S/cm) have been developed but these also suffer from poor mechanical properties. Incorporation of plasticizers as well as nano fillers in polymer electrolytes, is of great importance for enhancing their performance in devices. In the recent years, researchers came up with an idea to make the use of ionic liquids in polymer electrolytes to address the problem of low ionic conductivity of polymer electrolytes at room temperatures as well as to keep good electrochemical and mechanical properties. The optimized ionic conductivity value of the order of ∼10⁻³ S/cm has been observed by different workers at different concentrations of ionic liquids. Also, polymer gel electrolytes have been reported to possess high ionic conductivity (of the order of ∼ 10⁻² S/cm) at ambient temperature. However, despite possessing high value of ionic conductivity these gel electrolytes have poor mechanical and thermal properties. Hence, the modified polymer /gel electrolytes having optimized properties, are described in this review paper. An attempt has also been made to highlight the work of different researchers in the form of synthesis, characterization and analysis of different modified polymer electrolytes for their use in different ionic devices.