Single-ion Polyelectrolyte/ Mesoporous Hollow-Silica Spheres, Composite Electrolyte Membranes for Lithium-ion Batteries

A single lithium-ion polyelectrolyte composite membrane was designed and prepared. It consisted of lithiated Nafion®, propylene carbonate (PC) and mesoporous hollow silica spheres (MHSi). SEM and TEM analysis illustrated that the MHSi disperse uniformly in the membrane. The thermal stability of the composite membrane was tested using TGA which showed that the decomposition temperature is as high as 400 °C. The maximum PC absorbability was 127% and caused a 23.1% volume change. The transference number of the membrane was 0.94, which is very close to unity. The MHSi and PC in the membrane synergistically contributed to the lithium-ion conductivity of 2.29×10−4 S cm−1 at 25 °C. In addition, Li/LiFePO4 half-cells employing the subject prepared membrane without addition of any other lithium salt demonstrated acceptable performance. This new type of polymer membrane may find acceptable application in high energy lithium-ion batteries in the near future.