Hierarchical Li4Ti5O12 nanosheet arrays anchoring on carbon fiber cloth as ultra-stable free-standing anode of Li-ion battery

Abstract

A flexible, free-standing composite anode with Li4Ti5O12 nanosheet arrays anchoring on plain-weaved carbon fiber cloth (LTO@CC) is prepared by a hydrothermal and post-annealing process assisted by a TiO2 seed layer. The LTO@CC anode free from polymeric binder and conducting agent exhibited much higher lithium storage capacity and cycling stability than the conventional slurry-processed electrode using the dandelion-like Li4Ti5O12 microspheres prepared by the same hydrothermal process. A high specific capacity of 128.8mAhg−1 was obtained at a current rate of 30C (1C = 175mAg−1), and almost negligible capacity loses was observed when the cell was cycled at 10, 20 and 30C each for 100 cycles. The carbon fiber matrix contributed to Li storage at low current rate, but the LTO nanosheet arrays have played the dominant role on the excellent rate capability. The improved electrochemical performance can be attributed to the synergetic effect between the hierarchical Li4Ti5O12 nanosheet arrays and the carbon fiber matrix, which integrated short Li+ diffusion length, three-dimensional conductive architecture and well preserved structural integrity during the high rate and repeated charge-discharge measurements.