2013 Volume 121 Issue 1416 Pages 723-729
Development of all solid-state Li secondary based on the use of dry polymer or inorganic electrolytes is vital as they will be free of solvent leakages and improve inflammability. However, both are still under development for many years due to low ionic conductivity, poor mechanical property and/or large internal impedance associated to poorly defined interfaces. In this paper, we report on a preparation and physicochemical property of mesoporous silica (MPS)/Li conductive polyethylene oxide (Li-PEO)-based polymer hybrid electrolytes (MPS+Li-PEO), and electrochemical performance of the Li/MPS+Li-PEO/LiFePO4 cell. The hybrid electrolytes showed an improvement of Li+ transportation number and a decrease of melting point and glass transition temperature, indicating a positive hybrid effect, or deviation from rule-of-mixtures behavior. The Li/MPS+Li-PEO/LiFePO4 cell showed a stable charge–discharge capacity of >70 mA h g−1 for 100 cycles at moderate temperature of 60°C and rate of 0.2 C, whereas severe capacity fade began after several of cycles for the cell using conventional Li-PEO electrolyte. AC impedance measurements revealed that the interface Li exchange between electrode and electrolytes related to the stable cyclic performance for the cell using hybrid electrolytes.