Synthesis of hierarchical NiO microsphere with waxberry-like structure and its enhanced lithium storage performance

This work reports a facile synthesis of hierarchical NiO microspheres with a waxberry-like structure by one-pot hydrothermal reaction followed by thermal annealing. We detected the composition of precursor by using two-dimensional detector X-ray diffractometer (XRD2). In addition, XRD, TG, SEM, TEM and BET measurement were used to characterize the structural properties of the as-prepared materials. The XRD result showed that the precursor has been completely transformed into NiO materials by calcination at 300 degrees C (denoted as NiO-300). Moreover, thanks to the well conservation of hierarchical structure consisting of needle-like nanoparticles in NiO-300 sample, the charge capacity can be stabilized at 597.8 mAh g(-1) reversibly when cycled 100 times at a relatively high current density of 0.7C which show a very competitive capacity compared with other nano-structure NiO materials and commercial NiO material. It also showed high rate capability, the reversible charge capacity is still retained to 370.3 mAh g(-1), even for the condition of 4.46C (high rate). This NiO-300 material's superior electrochemical performance should be exclusively attributed to the well conserved hierarchical waxberry-like structures, which shortens the diffusion pathways of lithium ions and electrons transfer as well as accommodate the drastic volume change during electrochemical charge/discharge process. (C) 2015 Elsevier B.V. All rights reserved.