The Electric Properties of Surface Coating with CePO4 and M3(PO4)2 (M=Mg, Zn) on Li4Ti5O12 for Energy Storage Capacitor

The Li 4 Ti 5 O 12 of anode material for the hybrid capacitor was coated using CePO 4 , M 3 (PO 4 ) 2 (M=Mg, Zn). The capacitance of phosphate coated Li 4 Ti 5 O 12 was found to be lower than that of Li 4 Ti 5 O 12 , whereas the equivalent series resistance was higher than that of Li 4 Ti 5 O 12 . With an increase in cycle number, the base of cylindrical cell exhibited swelling due to gas generated from the reaction between Li 4 Ti 5 O 12 and electrolyte. The swelling cycle number of phosphate coated Li 4 Ti 5 O 12 was higher than that of Li 4 Ti 5 O 12 due to improvement in electrochemical stability. Based on the results, it is proposed that phosphate coating can be employed as a barrier layer to control the gassing reaction by isolating the Li 4 Ti 5 O 12 particle from electrolyte solution.