A novel polyvinylidene fluoride/microfiber composite gel polymer electrolyte with an interpenetrating network structure for lithium ion battery

• A simple method has been developed to fabricate PVDF/microfiber composite membrane with an interpenetrating network structure.
• PVDF/microfiber composite gel polymer electrolyte membrane, for the first time, as a separator for lithium ion battery.
• The PVDF/microfiber composite gel polymer electrolyte membrane has good mechanical strength.
• The cell assembled with PVDF/microfiber composite gel polymer electrolyte membrane exhibits good electrochemical performance.

In this present study, macroporous PVDF/microfiber composite gel polymer electrolyte with an interpenetrating network structure was prepared by phase inversion method. The structure and electrochemical performance of the composite membrane were characterized by scanning electron microscopy, stress-strain testing, charge/discharge testing etc. These results exhibit that its electrochemical and mechanical properties were improved by introducing the microfiber network into the macroporous PVDF matrix to form an interpenetrating network structure. The results from electrochemical measurements show that the composite gel electrolyte is stable, and the cells with the PVDF/microfiber network composite membrane have higher discharge capacities and better cycling stability than that assembled with pure macroprous PVDF membrane.