Dual Functions of Carbon in Li4Ti5O12/C Microspheres

Spinel Li4Ti5O12 has become an alternative material to replace graphite anodes in terms of solving safety issues and improving battery life-time. Unfortunately, as Li4Ti5O12 is an insulator, the low electrical conductivity becomes a major drawback, as it is unfavorable to higher rate capability. In addition to the low electronic conductivity, severe gassing during charge/discharge cycles is a critical but often-overlooked problem of Li4Ti5O12 batteries. Li4Ti5O12/C microspheres were prepared by assembling the nano-Li4Ti5O12 (50-300 nm) with pitch derived pyrolytic carbon. It was found that the coated carbon in Li4Ti5O12/C microspheres can effectively inhibit gassing and Mn deposition in LiMn2O4//Li4Ti5O12 battery. Carbon can also significantly improve rate capability and cycling performance comparedwith that of Li4Ti5O12 microspheres without carbon due to stable interface and superior electronic conductivity. (C) The Author(s) 2014. Published by ECS. All rights reserved.