An Impedance Study on Porous Carbon/Lithium Titanate Composites for Li-Ion Battery

Abstract

The electrode structure affects the charge-transfer process, electronic conduction, mass transport within pores, and therefore electrochemical performance of batteries 1. In this study, a hierarchical carbon network with hollow core and mesoporous shell (HCMS) 2,3 and activated carbon (AC) are employed as supports for Li4Ti5O12 (LTO) anode material. LTO/HCMS composite shows higher capacity than LTO/AC composite under high-rate and low-temperature conditions. In order to study the performance-structure relationship, electrochemical impedance spectroscopy (EIS) technique with transmission line model (TLM), together with material characterization, are utilized to study the electronic conduction process, mass transport within the pores and the charge-transfer process of LTO/C composites and carbon supports.