Facile synthesis and electroactivity of 3-D hierarchically superstructured cobalt orthophosphate for lithium-ion batteries

The synthesis of materials with ordered or self-assembled superstructures provides opportunities to tune the material's physical and chemical properties for energy storage device applications. Here, we report the synthesis of a three-dimensional (3-D) hierarchical cobalt orthophosphate (Co₃(PO₄)₂) compound by a facile wet-chemical route at a low temperature (65 °C), followed by a dehydration process (600 °C). The resulting cobalt orthophosphate compounds were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and thermogravimetric (TG)/differential thermal analysis (DTA). The compounds' electrochemical behavior for lithium-ion batteries was also investigated. Analysis revealed the flower-like microarchitecture of the cobalt orthophosphate compound, in which porous nano-plates with an average thickness of 150 nm were self-assembled into a microscale superstructure. As an anode material for lithium-ion batteries, the optimal cobalt orthophosphate compound showed stable cycle performance (0.083% capacity decay per cycle over 100 cycles).