Journal of Power Sources, Vol.349, 52-56, 2017
Novel insights into the charge/discharge characteristics of spherical porous Li4Ti5O12 co-coated with carbon and metal
The charge/discharge characteristics of metal (Cu or Ag) and carbon co-coating spherical porous Li4Ti5O12 are investigated in this paper. And the Li4Ti5O12/C-Ag presents the highest reversible capacity of 189.0 mAh g(-1) among the four samples of Li4Ti5O12, Li4Ti5O12/C, Li4Ti5O12/C-Cu and Li4Ti5O12/C-Ag. Furthermore, the charge/discharge tests of the Li4Ti5O12/C-Ag electrode without conductive carbon show low initial reversible capacity of 17.6 mAh g(-1) during charge -discharged at 0.1C (1C = 170 mA), suggesting that the conductive carbon is necessary for this kind of active material. The result also shows that a higher reversible capacity of about 110 mAh g(-1) can be obtained by decreasing the discharging current density to 0.005C. Based on the low bulk electronic conductivity of Li4Ti5O12 can be improved by lithium insertion, an improved charge -discharge method is developed by discharging the Li4Ti5O12/C-Ag electrode at 0.005C for 20 h to improve its electronic conductivity and further discharge at 0.1C to shorten the discharge time.(C) 2017 Elsevier B.V. All rights reserved.