HQ Asymmetric Super Capacitor: Graphite-Li4Ti5O12/Ionic Liquid/Carbon

Hybrid supercapacitor that contain high-surface-area carbon and metal oxide electrodes are attracting interest for use in electrochemical devices. Metal oxide electrodes containing Li4Ti5O12 in liquid electrolytes (ionic liquid or nonaqueous liquid) were investigated. A new procedure developed at Hydro Quebec produced Li4Ti5O12 powders with diameters in the range of 100 nm. At high-rate (1 minute) charge-discharge, the hybrid supercapacitor had an average voltage of about 2.21 V, with 85% nominal capacity. These hybrid supercapacitors also exhibited a very long cycle life of >20,000 cycles at high- rate charge-discharge. The results of this study demonstrate that the Li4Ti5O12-based electrochemical system has attractive characteristics for high-power application such as in portable devices and HEVs