The effects of high temperature solid state synthesis condition on the structure,micro-morphology,pore diameter distribution and electrochemical properties of spinel Li_4Ti_5O_ 12 for an Li_4Ti_5O_ 12 /C hybrid electrochemical capacitor were investigated by XRD,SEM,BET and charge/discharge tests. The results show that the Li_4Ti_5O_ 12 sample obtained at 800?℃ for 2?h has rich mesopores and exhibits better electrochemical properties. Its BET surface area reaches 4.4?m2·g -1 ,the specific capacity reaches ap...