The Synthesis of Hyperbranched Star Polymeric Ionic Liquid and the Application in Polymer Electrolyte
This research provides an effective approach to synthesize a hyperbranhced star polymeric ionic liquid (HBPS-(PVIMBr)x) with hyperbranched polystyrene core and poly(1-Butyl-3-Vinylimidazolium Bromide) arms via combination of atom transfer radical self-condensing vinyl polymerization (ATR-SCVP) and RAFT polymerization. The synthesis process ensures the well structural controllability and consistency that all of the arms of star polymers are ionized. The obtained star polymeric ionic liquid shows good thermal stability with the initial thermal decomposition temperature above 290°C. Moreover, after anion exchange, the TFSI- anions based hyperbranched star polymeric ionic liquid (HBPS-(PVIMTFSI)x) is used as all-solid polymer electrolyte for lithium-ion batteries. The electrolytes (HBPS-(PVIMTFSI)x/LiTFSI) fabricated by solution casting method exhibit high room temperature ionic conductivity (4.76×10-5 S cm-1, the quantitative ratio of LiTFSI to polymer matrix is 40%), wide electrochemical window (4.9 V) and great interfacial compatibility.