A facile way to prepare carbon-coated Li4Ti5O12 porous fiber with excellent rate performance as anode in lithium ion battery

Abstract

Carbon is an economy and effective material for improving the electron conductivity of Li4Ti5O12, coating carbon on Li4Ti5O12 is commonly through the means of calcinating the mixture of titanium, lithium and organic compounds in an inert atmosphere, which needs a careful control to avoid the reduction of Ti4+ in Li4Ti5O12 by the in-situ formed carbon. In this work, a facile way is applied to fabricate carbon on Li4Ti5O12 by using filter paper to absorb the solution containing Ti(OC4H9)4 and LiAC with a calcination at 700 °C in air. The formation of carbon on Li4Ti5O12 mainly related with the swelling property of the crystalliferous region in cellulose fiber. TEM image shows Li4Ti5O12 particles have the average diameter about 100 nm, which are coated by a thin layer of carbon with the thickness around 5 nm, and Li4Ti5O12 particles connect with each other by carbon, forming porous fiber, which facilitates the transfer of electron and Li+. In comparison with Li4Ti5O12 synthesized by sol-gel method, Li4Ti5O12/C present superior rate capability with the discharge capacity of about 165 mAh g−1 at 0.2 C and 141 mAh g−1 at 20 C.