Surface engineering of graphite anode material with black TiO2-x for fast chargeable lithium ion battery

Abstract

One of the most important challenges in the improvement of the lithium ion battery (LIB) for electric vehicle (EV) applications is its fast charging capability. However, currently used graphite anode materials cannot meet this requirement for EVs. Herein, we demonstrate that surface modification of graphite using oxygen-deficient black titanium oxide (TiO2−x) is an efficient way to improve the fast charging capability of graphite anode material for LIB. The proposed surface engineered anode material, 1 wt% TiO2-x coated graphite anode material, at a high rate of 5 C-rate, exhibited 98.2% of the capacity obtained at a rate of 0.2 C without any degradation of other performances. Full cell tests adopting LiCoO2 as a cathode material with TiO2-x coated graphite anode material also confirmed that the TiO2-x coating layer can improve the fast charging capability of graphite anode material. Such an improvement in the fast charging capability has mainly been attributed to the modified interface between the anode and the electrolyte by surface-engineering of the TiO2-x layer on the surface of graphite. These results show that the approach presented in this work, interfacial engineering of graphite using oxygen deficient TiO2-x, deserves to be regarded as one of the most promising ways to develop an anode material with fast charging capability for high power LIB for EV applications.