Solid Polymer Electrolytes with Flexible Framework of SiO2Nanofibers for Highly Safe Solid Lithium Batteries

Composite electrolytes consisting of polymers and three-dimensional (3D) fillers are considered to be promising electrolytes for solid lithium batteries owing to their virtues of continuous lithium-ion pathways and good mechanical properties. In the present study, an electrolyte with polyethylene oxide-lithium (bis trifluoromethyl) sulfate-succinonitrile (PLS) and frameworks of three-dimensional SiO(2)nanofibers (3D SiO(2)NFs) was prepared. Taking advantage of the highly conductive interfaces between 3D SiO(2)NFs and PLS, the total conductivity of the electrolyte at 30 degrees C was approximately 9.32 x 10(-5)S cm(-1). With a thickness of 27 mu m and a tensile strength of 7.4 MPa, the electrolyte achieved an area specific resistance of 29.0 omega cm(2). Moreover, such a 3D configuration could homogenize the electrical field, which was beneficial for suppressing dendrite growth. Consequently, Li/LiFePO(4)cells assembled with PLS and 3D SiO(2)NFs (PLS/3D SiO(2)NFs), which delivered an original specific capacity of 167.9 mAh g(-1), only suffered 3.28% capacity degradation after 100 cycles. In particular, these cells automatically shut down when PLS was decomposed above 400 degrees C, and the electrodes were separated by the solid framework of 3D SiO(2)NFs. Therefore, the solid lithium batteries based on composite electrolytes reported here offer high safety at elevated temperatures.