Lithium titanate tailored by cathodically induced graphene for an ultrafast lithium ion battery

Abstract

Nonoxidative cathodically induced graphene (CIG) here incorporates conductive agents for Li<inf>4</inf>Ti<inf>5</inf>O<inf>12</inf> (LTO) anode materials. The tailored LTO/CIG composite is fabricated by controlled hydrolysis of tetrabutyl titanate in the presence of nonoxidative defect-free cathodically induced graphene (CIG) and oxalic acid in a mixed solvent of ethanol and water, followed by hydrothermal reaction and a calcination treatment. Due to the introduction of defect-free graphene, the resulting LTO/CIG composite shows an excellent electrical conductivity (1.2 × 10^-4 S cm ^-1) and Li⁺ diffusion coefficient (1.61 × 10 ^-12 cm² s^-1). As a result, the tuned LTO/CIG composite exhibits outstanding electrochemical performance, including excellent cycling stability (the capacity retention ratios after 500 cycles at 0.5 C is 96.2%) and a remarkable rate capability (162 mAh g^-1 at 10C, 126 mAh g^-1 at 100 C). A specific energy of 272 Wh kg^-1 at power of 136 W kg^-1 is observed when cycling against Li-foil. Even during 36 s of charge/discharge, the specific energy of LTO/CIG composite remains at 166 Wh kg^-1. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.