Study on the effect of Li doping in spinel Li 4+xTi 5−xO 12 (0 ⩽ x ⩽ 0.2) materials for lithium-ion batteries

Abstract

The effect of Li doping in spinel Li 4+ x Ti 5− x O 12 (0 ⩽ x ⩽ 0.2) materials on the structural and electrochemical properties were investigated. The ratio of the capacity in the voltage plateau (1.5 V) to the overall discharge capacity for Li 4.1Ti 4.9O 12 ( x = 0.1) and Li 4.2Ti 4.8O 12 ( x = 0.2) were higher than that of Li 4Ti 5O 12 especially at high current rates due to their enhanced lithium-ion and electronic conductivity by the substitution of Ti atoms by Li atoms. With the increasing of Li doping amount, lithium-ion and electronic conductivity of Li 4+ x Ti 5− x O 12 increased, however its cycling stability was depressed when the Li doping was of x = 0.2. The Li doping of x = 0.1, the appropriate Li doping amount, showed improved rate capability and better high rate performance comparing to undoped Li 4+ x Ti 5− x O 12 ( x = 0).