Enhancing the rate performance of high-capacity LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 cathode materials by using Ti_4O_7 as a conductive additive

摘要

Magneli phase Ti4O7 with high electrical conductivity and chemical inertness is successfully prepared by the thermal reduction process. This material exhibits a large size (200 nm1 mu m) and a high surface area (3.52 m(2)g(-1)) by using TiO2 (P25) as the raw material, and six different ratios of this material are decorated on conventional electrodes made of acetylene black (AB). The morphological, structural, and electrochemical characteristics of Ti4O7-decorated LiNi0.8Co0.15Al0.05O2 (NCA) are compared with those of pristine NCA. The Ti4O7-decorated NCA electrodes demonstrate better cyclability and specific capacity than the pristine NCA owing to the improvement in stability and conductivity. Under a current density of 2000 mAg(-1), the electrode mixed with 0.5 wt% Ti4O7 delivers a capacity of 159 mAhg(-1), which is higher than that of the pristine electrode with a capacity of 94 mAhg(-1). The capacity retention is improved to 88% at 40 mAg(-1) after 50 cycles.