Highly porous disk-like shape of Co3O4 as an anode material for lithium ion batteries

A novel disk-like shape of Co3O4 with high porosity was synthesized by a facile hydrothermal approach followed by calcination at 485 °C for 2 h. In order to further confirm the crystal structure, morphology, particle size, surface area, and porosity of the sample, a series of corresponding characterization techniques were used. The disk-like shape of Co3O4 as an anode delivered excellent rate capability such as 510.5 mAh g−1 at 4.0 C, which is much higher than the theoretical capacity of commercial graphite anode (372 mAh g−1). However, the electrode could not recover the high capacity during the long-term cycling at various higher current rates due to the deformation of the structure as confirmed by the ex situ studies. It is believed that the obtained remarkable structural feature with numerous void pores within the structure may be helpful for short-term cycling due to the large contact areas between the electrode and the electrolyte and a shorter diffusion length for lithium ion insertion but unable to act as a buffer to relax the volume expansion/contraction and alleviate the structural damage of the electrode during long-term cycling.