Influence of sintering temperature and graphene additives on the electrochemical performance of porous Li4Ti5O12 anode for lithium ion capacitor

Porous L4Ti5O12 (LTO) nanoparticles were prepared by a precursor directed hydrothermal method followed by sintering. The influence of sintering temperature and graphene additives on the microstructure evolution and electrochemical properties of LTO for lithium ion capacitors (LICs) was investigated. Bare LTO with fine particle and porous microstructure can be obtained under low temperature sintering (600 degrees C), which can deliver a specific capacity of 65.2 mAh g(-1) at the current rate of 20C. With increasing temperature, the LTO particles are inclined to grow with coarse particle and the agglomerate state, deteriorating the electrochemical performances (14.3 mAh g(-1) at 20C). After introduction of graphene additives, LTO can be prepared with increased surface area, pore volume and electrical conductivity, which are beneficial for LTO to contact with electrolyte, shorten the lithium diffusion length and facilitate the electron and ion transport during lithiation/delithiation process, leading to the greatly improved electrochemical performances (102 mAh g(-1) at 20C). The LICs full cell using the LTO/graphene anode and activated carbon cathode was also evaluated. The decent energy/power densities (maximum energy/power densities are 44.0 Wh kg(-1) and 7200 W kg(-1), respectively) with excellent cycling stability (capacitance retention of 80% at a current density of 3.2 A g(-1) after 10000 cycles) show the promising application perspective. (C) 2017 Elsevier Ltd. All rights reserved.