Ammonolyzed MoO_3 Nanobelts as Novel Cathode Material of Rechargeable Li-Ion Batteries

摘要

Through a moderate ammonotysis method, nanobelts of α-MoO_3 can be modified to H_xMo(O, N)_3. When reaction temperatures are kept between 200-300 °C, gaseous NH_3 diffuses in-between the oxide layers and reacts with terminal oxygen sites of MoO_3. As a consequence, hydrogen is introduced into the layers and bonded to terminal oxygen, and together with the effect of nitradation, the unit cell volume significantly shrinks mostly along the b axis. The modified compound H_xMo(O, N)_3 exhibits not only better electronic conductivity, but also faster lithium ion mobility than regular MoO_3. In addition, this ammonolyzed MoO_3 exhibits enhanced electrochemical performance beyond MoO_3. In the potential window 1.5-3.5 V, the specific capacity of H_xMo(O, N)_3 can reach more than 250 A h kg~(-1) and was cycled 300 times without fading. It can be considered as a novel candidate cathode material with high specific charge for rechargeable Li-ion batteries.