Improvement of Tap Density of TiO_2(B) Powder as High Potential Negative Electrode

摘要

The shape and size of TiO_2(B) particles were controlled by ball-milling K_2Ti_4O_9, H_2Ti_4O_9 and TiO_2(B) powders to improve the tap density of TiO_2(B). It was found that only K_2Ti_4O_9 endured the ball-milling process and provided a fine TiO_2(B) powder after the ion-exchange and dehydration processes. In contrast, ball-milling of H_2Ti_4O_9 and TiO_2(B) powders resulted in a formation of a large amount of the rutile and anatase phase, respectively. In addition, a reduction of the spinning rate to 600 rpm suppressed the formation of the minor impurity of the anatase phase in the TiO_2(B) sample prepared from the milled K_2Ti_4O_9 powder. The resulting TiO_2(B) (M1-600) powder exhibited a high tap density of 0.71 g cm~(-3) and a high electrode density of 1.25 g cm~(-3), which were 2.37 and 1.29 times, respectively, higher than those of the pristine TiO_2(B). In charge/discharge tests, M1-600 exhibited a discharge of 213.1 mAh g~(-1), which is higher than that of the pristine TiO_2(B), with a good cycleability. It gave a discharge capacity of 80.1 mAh g~(-1) even at a high rate of 10 C.